Would adding a second layer of shrink tubing result run meaningful signal attenuation?

[powneill]

I am thinking about adding a second layer of shrink tubing that is white. The Maiana that I built will eventually end up on a sailboat in the tropics, bombarded by the sun, and my thought is that adding a white layer on top of the black shrink tubing should result in a little more reflectivity, hopefully reduce the heat soak a bit, and keep the electronics a bit cooler.

I haven't been able to find much in the way of data regarding how much signal attenuation results from a layer of your average shrink tubing, and I do not have the equipment required to test for signal loss.

Thanks much for any info!