Hey Mark
I’ve made my own matt also and was cheaper and better than any other thing on the market.
Mine consist’s of High Dense foam layer on the top, then Medium, Soft, Medium then another high dense layer on the bottom. The layer on the bottom is to help rocks pushing up through the matt and bottoming out. Its 6inch thick by 1.2m by 1m,
The fold looks like a Z (to thick for a taco style)… so its cut across rather than straight through. This is a little harder to get right but still easy as in reality its a six sided box, get ya measurements right and can’t go wrong.
I’ve then covered it in thick canvas, double stitched all the seems. Ive got pull tabs on the sides so ppl can quickly move it if you go off target.
I also got mine custom embodied, skys the limit mate!
If you got any questions or want some pictures, give me a email on allanjt at hotmail dot com