I have a question, it is about the glassing over the foam core for the turret. I take it your using an epoxy resin as I don't see the foam core melting away (yet -- I'm guessing you'll use gas or something afterwards to hollow it out).
I love the idea of the foam core sprockets and track pieces. are you casting them yourself? I would love to see and hear more about this. I never thought bout going this route before!