Last night after work I went searching (again) for a suitable material for the gaskets. I ended up in a Joannes fabric store, saw they had a little section for cosplay. There was a ton of rubbery coated spandex material. The one that caught my eye was a smooth semi gloss rubber. It reads as a grey in photos from the light reflection. But, over a textured cording for rib structure, a slight texture will probably be transfered through the fabric. I bought a piping/cording foot for my machine. This will allow me to lay the chord between the layers and sew right next to it. Looking at the reference photographs, it appears that the ribs have a D shape to them, meaning that the backing material was layed flat. I am going to sew up a test piece tonight and see where this gets me. If it is too pronounced, I will sew channels and insert cording like Tom has done.
Here is a pic of the fabric. Its black in person, light reflection is showing as a grey green color.