Closed cell foam is the answer. I f you're trying for a puffy or less rigid look look, don't glue to the foam, just at the edges and around on the back to complete.

Hi Jason,
First of all, nice job on the design. After more than 50 years of experience I've found that no matter what combination of a foot on your machine you can feel when you're close. Sewing 2, 3, 4 times to get closer will work but it is simply a waste of time. Don't buy new equipment, practice, practice, practice! Mastering a sewing machine is no different than a musical instrument!
Also, A very clean tight look can be achieved using 1/2 scrim on the faces, ( between the inserts), and 1/4 on the rest. Keep up the great work, hope this helps!

Over the years I've found all kinds of strange stuff, from ammunition to pornography. My best find however is, a few months ago I found a pair of pliers with the letters GM inscribed on them, buried in the side bolster of an original seat from a 1966 GTO. The seat had never been apart.

Try Lindsey and Hall in Los Angeles, they have a good selection of automotive houndstooth.

I am extremely blessed, a one man shop of 40+ years catering to custom rods and Restos. I'm as busy as ever, I won't wear a mask and if it becomes an issue with a customer they lose their slot. I refuse to buy into the panic however I do feel for those who have lost loved ones. My thoughts and hopes go out to all that are struggling during this unfortunate situation with confidence that we all will return to prosperity with the new normal.

Nice job!