Here is a progress update on the right-hand fiddle yard. I plan to start its left-hand companion after this one is finished so that I can learn from my mistakes. As you can see, there is quite a deep plywood frame, so as to match the scenic board. I plan to install sockets for the controller in one of the spaces underneath, and use this as the main control position (operating from the front). Spare surface space alongside the approach roads will probably see some loco storage spurs.
The turntable itself is mounted on a roller-bearing like the one shown below right. It came from Squires, I think. Six of the roller bearings shown below left are set into the framework to give the deck some free-rolling support. These came from Station Road Baseboards.
I have yet to finalise the manner of electrical connection, and to decide whether all roads should be live or not (the electrics will be dcc). Then I should be ready to attach the balsa trackbed and lay some track. I optimistically went for six roads. Between the two fiddle yards, this should house all of the stock I build for some years...!