Nice! What size is your tent? I'd be inclined to say 4 if the tent is square. If you get them right I think you'll be surprised at how big autos can get. I'm assuming you'll be sticking them in hydro.
hydro+autos =
The first hydro Auto I grew was a GSC from Fastbuds and it was bigger than every other auto I had grown before in soil. How are you starting them? I'd recommend using some kind of starter cube or rockwool as they need the best possible start. One of the main reasons for stunted autos are poor start where people handle the seeds with the roots out or over water them early on slowing them down. Then people try to transplant them which I think is a bad idea. No good will come of giving them any stress in the first 2 weeks. I start mine on low lighting (100w Led) for the first week then buy the end of the second week usually I'll have them under full power lighting. I'm looking forward to seeing you kill it with some autos!