I believe its 12,

but i at least try to make simply more rooms like with tank storage and theme them to specific things like nationalities, then you got quiet some space ^^

The great thing is, you can make a room layout with ground/walls and some stuff then save it easy to use for next room.

then you can be creative with each room

for me thats good enough tho :)

Yes, thats the total limit just to block players having ctd from lack of RAM. This is the result of our wrong doings with the optimization of the models, something we fixed for our next project but here we wont do it - just would require remaking all older models which we cant do at this moment