I glued camping mats to roof and sides of my hardtop 15 years ago and it is still there. One corner peeled back, I think the carpet spray glue was applied too thinly as the can ran out, but glued it back with some evostick I found in Nairobi. It also appeared that the spray adhesive had dried and became powdery, so a stronger contact glue may be the answer. Do a test strip and make sure the foam does not dissolve. I slept in the back in winter in UK and Spain with nil condensation and still use it at altitude in Africa with no problem. Carpet may be too heavy, rough open weave may not stick so well. Camping mats are really easy to cut and trim with a new sharp scalpel blade and are so lightweight. I also stuck thin but rigid plastic sheet over foam on side panels to prevent damage. Try Devon Conversions Ltd online they may give you some info.