how many plants in this space

I have a 12 x 12 x 8 room. I have 4 1000 watt hps lights.I am going to to use 3 gallon grow bags with fox farm ocean forrest soil. My question is how many plants would you put in this space? they will be only 12" tall when they go into thw flower room . so they shouldnt get more then 36-40 tall.lets here what you guys think.