Like most big MOCs that have been done, the initial build usually comprises of a key scene as a Proof-Of-Concept. In this case, the Clone Cadets pic was the one and the tremendous response to it made me decide to proceed with the whole training facility.
Hence, this first installment of the work-in-progress shows the pit where the first pic was taken. Only the immediate area shown around the first pic was built initially and that has been expanded to both side walls.
The side walls have walkways where the next batch of cadets wait for their turn. The current footprint is comprised of six 32x32 green baseplates that covers the backside of the facility and would most likely use up all the green bricks in stock just for the base.