I have a monster roll of 5mm blue EVA foam that is 66" wide. I cut a piece close to the dimensions of the Hennessy Double Bubble Radiant Pad-- 66" long x 29" wide and the shoulders and I slipped a bit so the foot end is 14" wide. It is 8oz on my scale. R-value should be around 0.7. My plan is to use it as a simple pad between my sleeping bag and the hammock fabric. The stuff molds to shape fairly well.

I have a bunch and I'm thinking about making an underpad with light line to hold it in place. Anybody try something like this?