I melted my soap into a bowl that I found in my kitchen. It worked well enough for me! if you shred or melt the soap then you can put in pretty much whatever you want

The poor man's strop from larry has a weird way of attaching to whatever you're hanging it from, and I think thats probably why the edges are curling up. Most hanging strops that I've seen have something flat across the hanging end of the strop that helps keep the whole thing flat when it's pulled tight.

Im not sure what you mean by "the top is not even with the bottom" so I can't really be helpful there