If it works it works. Everything matters though. Wall construction, direction of walls, how many linear footage of window and door edges. I used to work for a mechanical engineer doing load calculations through a program and those were all the inputs. I know in the commercial world we do 400 sq. ft. per ton.
I actually contacted the Mitsubishi rep in my area and that’s the size they recommended was a 3 ton hyper heat with inverter tech. 76% at -13F 100% at 23F. Decent system for the price.
The AC market is constantly evolving and there are systems like VRF and hyper heat that are very efficient. Heat recovery VRF are invaluable to the home grower as the system can extract heat from the grow rooms and distribute to the rest of the indoor units.
There is also technology that makes the units not just turn on and off, but run at reduced capacity to save electricity when a full load isn’t needed.