I spent about an hour soldering feeders to the turntable, and then soldered feeders to the track that will eventually lead from the turntable to the engine shed. It all works flawlessly.
Now, every inch of track is powered.
Next up, I will be continuing to work with my brother-in-law to configure the Arduino shield-stack, then will start programming.
Functionality of the Arduino will be super-simple (although I could make it more complex later on). The turntable will be selectable as an accessory (just like the switches), and will be able to turn 180 degrees clockwise and counter-clockwise with the push of a single button on the PowerCab.
By selecting a different address, the turntable will enter “nudge” mode. This way, if I need to align the deck with the tracks, I can nudge it a single click clockwise or counter-clockwise (the stepper motor moves 400 clicks with every rotation.
I’m hoping to start programming the Arduino tomorrow.