I have a question, what type of bearing are you going to use for the turntable. It will need to be supported over the whole surface and have extremely low noise levels, so low in fact that you may have trouble engineering it. Forgive me if i'm reading too much into this, but to cut a record involves physically cutting a groove in a disc. So the turntable have to be rigid to avoid any deflection when cutting and have no bearing noise (wow and flutter).