I make them.out of a wide roofrack strap and EVA foam.For the front feet these work perfect.Light,comfy,no water absorption,very low profile.
Just use contact glue or 3m Super77.
The back strap i am always stepping on when my back foot is out which is a lot so i use two straps sewn together so i can insert a clear plastic "batten" in the sleeve to make it stay open after getting crushed.
Maybe a silicon rubber insert would be the best for that back strap.