I am planning an On30 layout that will fill a room 23x10 feet, and operate with DCC control.  In order to install electricity for the room, I need to know how many 20 amp circuits I need to pull.  I currently have the following On30 motive power, all Bachmann:

(2) 2-6-0
(1) T-Boiler Two-Truck Shay
(1) Baldwin Outside Frame 2-8-0 Consolidation
(4) Porters
(1) Baldwin 2-4-4 Forney
(1) American 4-4-0

Eventually I hope to run all of them on DCC, with sound.  I have about a dozen passenger cars and cabooses with Bachmann factory installed lights in them.  I will not be running the structure lighting from my DCC system, and since the layout period is going to be about 1915, I will not be doing a lot of electric signaling.  I will have to have some remote control turn-outs, but not running on the DCC system.  I am assuming I need one 20 amp circuit just for room lighting, so my question is...do I need one or two more 20 amp circuits to run the DCC, boosters, etc.?

Thanks,

Mark