diff --git a/docs/_templates/demo.html b/docs/_templates/demo.html
index 20bf2ac..ee463b0 100644
--- a/docs/_templates/demo.html
+++ b/docs/_templates/demo.html
@@ -1,7 +1,7 @@
 <div class="work-sidebar {% if not lite_links %}work-sidebar-fail{% endif %}">
   <div class="work-sidebar-header">
     <i class="fas fa-{% if lite_links %}square-arrow-up-right{% else %}bomb{% endif %}"></i>
-    Preview Site
+    current preview site
   </div>
   <div class="work-sidebar-content">
     <blockquote>
diff --git a/docs/_templates/new-form.html b/docs/_templates/new-form.html
index 7395c99..b731ea9 100644
--- a/docs/_templates/new-form.html
+++ b/docs/_templates/new-form.html
@@ -1,23 +1,16 @@
 <style>
-  .bd-footer,
-  .header-article-items {
-    display: none;
-  }
   .bd-main .bd-content .bd-article-container .bd-article {
     padding: 0;
   }
   .bd-sidebar-primary {
     padding-bottom: 0;
   }
-  footer {
-    display: none;
-  }
 </style>
 
 <div class="work-sidebar">
   <div class="work-sidebar-header">
     <i class="fas fa-code-pull-request"></i>
-    Request Preview Site
+    start pull request
   </div>
   <div class="work-sidebar-content">
     <form id="propose" method="get" action="https://github.com/deathbeds/jupyak/new/main" target="_blank">
@@ -45,7 +38,7 @@
 }
 </script>
 <script type="module">
-  document.addEventListener('DOMContentLoaded', async () => {
+  document.addEventListener('DOMContentLoaded', async function(){
     const form = document.querySelector('form#new');
     const preview = document.querySelector('#toml-preview');
     const selector = 'form#new input[type="text"], form#new select';
diff --git a/docs/conf.py b/docs/conf.py
index f37a33c..d990c81 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -42,7 +42,6 @@
 
 # sphinx config
 extensions = [
-    "sphinx.ext.intersphinx",
     "sphinx.ext.viewcode",
     "myst_nb",
     "sphinx.ext.autosectionlabel",
@@ -55,10 +54,6 @@
 autosectionlabel_prefix_document = True
 myst_heading_anchors = 3
 
-intersphinx_mapping = {
-    "python": ("https://docs.python.org/3", None),
-}
-
 mermaid_version = ""
 mermaid_init_js = "false"
 
@@ -102,7 +97,6 @@
 html_sidebars = {
     "*": ["page-toc", "edit-this-page", "sourcelink"],
     "graph": [],
-    "new": ["new-form"],
 }
 
 if REPO_INFO is not None:
diff --git a/docs/new.md b/docs/new.md
index dfcafad..7514643 100644
--- a/docs/new.md
+++ b/docs/new.md
@@ -1,6 +1,8 @@
 # request a preview site
 
-> make selections below, then use the sidebar to start a new Pull Request
+> Make selections below for the most common configuration options, then use the 
+> _start pull request_ form to be redirected to GitHub.
+> A large number of other configuration options are _possible_, but are not yet fully described.
 
 <style>
 
@@ -88,7 +90,15 @@ display: none;
 </style>
 <form id="new">
 
-<h2>repos</h2>
+<fieldset>
+<legend><h2>customize GitHub checkout</h2></legend>
+
+<blockquote>
+All of the repositories below will be checked out at the current <code>main</code> branch as a <em>baseline</em>. 
+Check one or more repos to provide use a differnt branch, PR, or tag, or provide one or more PRs to 
+<i>merge with</i> it, and/or customize the <a href="https://git-scm.com/docs/merge-strategies" target="blank">merge strategy and options</a> to work around merge conflicts.
+</blockquote>
+
 
 <input type="checkbox" name="show-repo-traitlets" id="show-repo-traitlets"/>
 <label class="show-repo-label" for="show-repo-traitlets">traitlets</label>
@@ -1361,4 +1371,107 @@ title="add space-delimted -X options for the merge strategy"
 
 </tbody>
 </table>
-</form>
\ No newline at end of file
+
+<fieldset>
+<legend>customize JupyterLite</legend>
+
+<blockquote>
+If given, an optional <a target="_blank" href="https://gist.github.com/">gist</a> will be cloned 
+to provide the content of the JupyterLite site.
+If the gist contains <code>jupyter_lite_config.json</code> and/or <code>jupyter-lite.json</code>,
+this will be merged into the generated 
+<a target="_blank" href="https://jupyterlite.readthedocs.io/en/latest/howto/configure/config_files.html">configuration</a>
+of <code>jupyter lite build</code> and the runtime application.
+</blockquote>
+
+<input id="lite-gist" 
+type="text"
+name="lite|gist" 
+pattern="^$|^[a-z\d]{20,}$"
+placeholder="gist ID"
+/>
+<label for="lite-gist">the gist ID must be empty, or contain 20+ letters and numbers</label>
+</fieldset>
+</form>
+<style>
+.bd-main .bd-content .bd-article-container .bd-article {
+padding: 0;
+}
+.bd-sidebar-primary {
+padding-bottom: 0;
+}
+</style>
+
+<div class="work-sidebar">
+<div class="work-sidebar-header">
+<i class="fas fa-code-pull-request"></i>
+start pull request
+</div>
+<div class="work-sidebar-content">
+<form id="propose" method="get" action="https://github.com/deathbeds/jupyak/new/main" target="_blank">
+<label for="toml-preview"><code>jupyak_config.toml</code> contents</label>
+<textarea
+required="true"
+id="toml-preview"
+name="value"
+spellcheck="false"
+placeholder="# make choices in the form"
+></textarea>
+<input type="hidden" name="filename" value="jupyak_config.toml"/>
+<br/>
+<button class="btn btn-success" form="propose">
+<i class="fas fa-code-pull-request"></i> New Pull Request
+</button>
+</form>
+</div>
+</div>
+<script type="importmap">
+{
+"imports": {
+"json2toml": "https://cdn.skypack.dev/pin/json2toml@v6.0.0-d8Y8va9lNUE85BZ5GSQ2/mode=imports,min/optimized/json2toml.js"
+}
+}
+</script>
+<script type="module">
+document.addEventListener('DOMContentLoaded', async function(){
+const form = document.querySelector('form#new');
+const preview = document.querySelector('#toml-preview');
+const selector = 'form#new input[type="text"], form#new select';
+const inputs = [...document.querySelectorAll(selector)];
+const split_fields = ['merge_with', 'merge_options'];
+async function update() {
+const json2toml = (await import('json2toml')).default;
+const config = find_config();
+preview.value = json2toml(config);
+}
+function find_config() {
+const config = {};
+const data = new FormData(form);
+for (const [name, value] of data.entries()) {
+if(document.querySelector(`input[name="${name}"]:invalid`)) {
+continue
+}
+let bits = name.split("|");
+if(value.trim() === "" || bits.length == 1){
+continue;
+}
+let current = config;
+for(const bit of bits.slice(0, -1)) {
+if(!current[bit]) {
+current[bit] = {};
+}
+current = current[bit];
+}
+let last_bit = bits[bits.length - 1];
+current[last_bit] = (
+split_fields.includes(last_bit) ?
+value.split(/[\s\n]+/):
+value
+);
+}
+return config;
+}
+inputs.map((input) => input.addEventListener('input', update))
+})
+
+</script>
diff --git a/src/jupyak/tasks/_form.ipynb b/src/jupyak/tasks/_form.ipynb
index a430f4b..5188ba9 100644
--- a/src/jupyak/tasks/_form.ipynb
+++ b/src/jupyak/tasks/_form.ipynb
@@ -21,6 +21,7 @@
     "from pathlib import Path\n",
     "\n",
     "import importnb\n",
+    "import IPython\n",
     "import jinja2"
    ]
   },
@@ -43,7 +44,7 @@
    "source": [
     "with importnb.Notebook():\n",
     "    from jupyak.tasks import load_tasks\n",
-    "    from jupyak.tasks._yak import Repo, Yak"
+    "    from jupyak.tasks._yak import Yak"
    ]
   },
   {
@@ -55,18 +56,7 @@
    "source": [
     "def load_yak():\n",
     "    load_tasks()\n",
-    "    return Yak({\"pr\": {}})"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "id": "adbc58fe-c2a6-4ef7-859a-a88546a60d15",
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "def make_repo(repo: Repo):\n",
-    "    return []"
+    "    return Yak({\"repos\": {}})"
    ]
   },
   {
@@ -77,7 +67,15 @@
    "outputs": [],
    "source": [
     "REPOS_TMPL = r\"\"\"\n",
-    "<h2>repos</h2>\n",
+    "<fieldset>\n",
+    "<legend><h2>customize GitHub checkout</h2></legend>\n",
+    "\n",
+    "<blockquote>\n",
+    "All of the repositories below will be checked out at the current <code>main</code> branch as a <em>baseline</em>.\n",
+    "Check one or more repos to provide use a differnt branch, PR, or tag, or provide one or more PRs to\n",
+    "<i>merge with</i> it, and/or customize the <a href=\"https://git-scm.com/docs/merge-strategies\" target=\"blank\">merge strategy and options</a> to work around merge conflicts.\n",
+    "</blockquote>\n",
+    "\n",
     "{% for name in yak.repos %}\n",
     "    <input type=\"checkbox\" name=\"show-repo-{{ name }}\" id=\"show-repo-{{ name }}\"/>\n",
     "    <label class=\"show-repo-label\" for=\"show-repo-{{ name }}\">{{name}}</label>\n",
@@ -213,6 +211,48 @@
     "    return [jinja2.Template(REPO_STYLE_TEMPL).render(yak=yak)]"
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "80c59837-bc25-4571-9c28-bcb61dac930e",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "LITE_TMPL = r\"\"\"\n",
+    "<fieldset>\n",
+    "<legend>customize JupyterLite</legend>\n",
+    "\n",
+    "<blockquote>\n",
+    "If given, an optional <a target=\"_blank\" href=\"https://gist.github.com/\">gist</a> will be cloned\n",
+    "to provide the content of the JupyterLite site.\n",
+    "If the gist contains <code>jupyter_lite_config.json</code> and/or <code>jupyter-lite.json</code>,\n",
+    "this will be merged into the generated\n",
+    "<a target=\"_blank\" href=\"https://jupyterlite.readthedocs.io/en/latest/howto/configure/config_files.html\">configuration</a>\n",
+    "of <code>jupyter lite build</code> and the runtime application.\n",
+    "</blockquote>\n",
+    "\n",
+    "<input id=\"lite-gist\"\n",
+    "     type=\"text\"\n",
+    "     name=\"lite|gist\"\n",
+    "     pattern=\"^$|^[a-z\\d]{20,}$\"\n",
+    "     placeholder=\"gist ID\"\n",
+    "     />\n",
+    "<label for=\"lite-gist\">the gist ID must be empty, or contain 20+ letters and numbers</label>\n",
+    "</fieldset>\n",
+    "\"\"\""
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "4b128fc0-36ad-463d-a1ff-8bfe0e3a4ffe",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def make_lite_form(yak: Yak):\n",
+    "    return [jinja2.Template(LITE_TMPL).render(yak=yak)]"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
@@ -225,7 +265,8 @@
     "    chunks = []\n",
     "    style_chunks = []\n",
     "    script_chunks = []\n",
-    "    for trait_name, value in yak.trait_values().items():\n",
+    "    for trait_name in [\"repos\", \"lite\"]:\n",
+    "        value = yak.trait_values()[trait_name]\n",
     "        maker = globals().get(f\"make_{trait_name}_form\")\n",
     "        if maker:\n",
     "            chunks += maker(yak)\n",
@@ -253,16 +294,31 @@
    "source": [
     "def write_form(dest: Path, **options):\n",
     "    dest.parent.mkdir(parents=True, exist_ok=True)\n",
+    "    final_tmpl = dest.parent / \"_templates/new-form.html\"\n",
     "    chunks = [\n",
     "        \"# request a preview site\",\n",
     "        \"\",\n",
-    "        \"> make selections below, then use the sidebar to start a new Pull Request\",\n",
+    "        \"> Make selections below for the most common configuration options, then use the \",\n",
+    "        \"> _start pull request_ form to be redirected to GitHub.\",\n",
+    "        \"> A large number of other configuration options are _possible_, but are not yet fully described.\",\n",
     "        \"\",\n",
     "        *make_form(),\n",
+    "        final_tmpl.read_text(encoding=\"utf-8\"),\n",
     "    ]\n",
     "    txt = re.sub(r\"^ +\", \"\", \"\\n\".join(chunks), flags=re.M)\n",
     "    dest.write_text(txt, encoding=\"utf-8\")"
    ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "7ac0c6c3-a69b-4e5e-bf55-1dcc2449f283",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "if __name__ == \"__main__\":\n",
+    "    IPython.display.display(IPython.display.HTML(\"\\n\".join(make_form())))"
+   ]
   }
  ],
  "metadata": {