Well, okay then, but if I put a fair sized marble at one end will it roll all the way to the other end!?

Very nice - wish I had such a place. I do, at least, finally have a dedicated table, 4' x 12' which can expand to 16' length. Now I just need to clear it off and play on it!
Looking forward to your completion so you can get on to those other highly enjoyed posts about your actual miniatures.