I have 5 autos. Running into slight room probs. But if i took the 5th one out of the middle would be much better. Go 4. With the expectations of bring 3 to harvest. 1 or 2 might die in pre flower, or late veg. So, have a little back up. And if it gets to bad with 4. Just get rid of your most troublesome plant/runt. I use a 70x70 have a look at the room. With LST done right you'll fit 4, 2-3 fems max. Best of luck.