How many plants? I'm just about done with my 3 ladies I had in there, I feel like I could of used more space with more plants. like 5 more in there. Plausible?
Yes. It all depends on what strains and how long you plan on vegging them for. Single cola plants are usually better for a setup like this. I got 20 plants SoG style wall-to-wall under a 600hps in a 4x4.5ish space. I'm pushing the limits with my setup, but honestly the sky is the limit once you add some mylar, and start throwing in techniques like LST/Topping/Pinching/Pruning. Good luck, and you may as well get every square inch out of your setup.