I found the foam only works with small projects using thinner 2-3 oz. leathers.
It doesn't have enough pressure for molding thick leather.
I tried the large gap foam hoping to get more expansion from it but didn't get any better results.
There might be another product out there but insulating foam just isn't strong enough.
The advantage is you can fill shallow, odd shapes with the foam, it worked really well on the pick case.
I'm back to using wood and now wood or clay to match the mold and getting great results, a huge improvement over tacking leather around a wooden block and trying to form it.
Kevin.