So your not messing around I see haha. I just Googled that closet and its pretty wild. Are you going to be using it for a perpetual harvest? And if so, will you be cloning or going from seed? Totally cool if you don't know yet.
Personally, even when I keep my plants small I like at least 1 sq ft per plant, so I'd try to have 3 in flower at any given time in that closet, at least to start. You could easily have 6+ in various stages of veg in the other side ready to go in as you harvest each plant.