I just started my Jabba's throne room display. I'm building it in a bookshelf, so it's more of a stage seeing everything will be on one side facing out. I have most of the flooring rough cut, and I started on the main archway over Jabba's throne. A good trick when mocking up foam walls is to use scewers cut short, stick em under the wall section pointy end out, place it, and jam it into the floor. Helps hold when gluing too, in addition to clamps. Well, that's what I do anyway.