Just curious what kind of foams you're using for backpack shoulder straps, framesheets, and hipbelts
Closed cell EVA or PE. Minimum of EVA 40 or PE 40 - the lighter stuff fails under load. Open cell is useless. Reconstituted foam is poor quality - more glue line than foam. Neoprene is very high quality, but expensive. The really light stuff is a bit fragile.