I was thinking of going 3x3 for 4-3 gallon smart pots, I'll go 7ft high to help with the heat. I have a 200CFM fan from HTGsupply with a 200cfm filter. On the bottom I was thinking on putting in vents like you see in a home with forced air heat. Those are adjustable to allow more or less air. I was going to do 3 sides with those vents. Any other helpful advice or design flaws please speak up. I'd like to get some input on it. I'm running a 400HPS in this