Hi, I'm new to this site, so I don't know exactly where to even post this question:

I want to scratchbuild a turntable, about mid 1930's or so, USA. It will be in HO, and about 13" in diameter, and I want the bridge to be wood trestle rather than steel plate. I know the ultimate answer is "It depends", but I am trying to get an idea of about HOW DEEP the pit should be. I am hoping maximum about 1 1/2" - about 12-14' in scale (the thickness of a 2x4) -  but I can add to that if needed.