help finding the right material
 

So new project up...my Stanley radio ear pro and Howard Leigh's take the same ear piece. They don't make a gel one for them so I thought I'll do it myself. The first prototype I just replaced the foam with a gel material, turned out ok but I wanna make it better. So what I need help with is sourcing materials for these.
I have the gel
I have the back plastic (thin kydex so if you can think of something cheaper and easy to get please enlighten me)
I need covering material, something that doesn't get gross w sweat was thinking gore-Tex but not sure that would be comfortable on the ears over long periods of time. Ideas?

make your own ear molds and make silicone pieces, smooth-on.com