I made another prototype, keeping the small size but making it so I'll actually be able to fit the bust in there. It turned out a little wide - I think I will make it a little more rectangular because it doesn't need the width. It's also quite a bit deeper - which it needs to be to fit the bust, though I think I'll make the final one a little smaller, and possibly not as round as a normal head so it doesn't stick out so much? 

another thing about making that section deeper is that the layers start quite a bit furthur back and it doesn't have quite the same effect