I'm on the hunt for a new mold for my salt soap. I've been using this (they were way cheaper when I bought them!) and I want something a little bigger, but shallower. I bought this one to try and the silicone is too thin, so they warp a lot. Any advice? I'm trying not to spend too much money, ideally I'd like 12 cavities (two 6 cavity molds is fine) for less than $15.