A few quetions

So my grow room is 36 inches long and 22.5 inches wide. about 6 foot tall.

have a euro reflector 400w hps connected to a 6 inch cheapo inline fan (40$?)

my light is a 2 foot 4 lamp high output t5

so far i'm doing 3 plants in 3 gallon containers, these are circular containers and fit perfectly under my t5. if I had any bigger in diameter containers they wouldn't be able to fit more under the light, because the lights only 2 foot long. The containers are about 10.5 inches in diameter.

The question I'm trying to ask is: Would I be better going of with few plants in square containers to get better use out of my space? How big should these get / be vegged? Can anyone provide a link to a large amount of plants growing in small containers under a 400w hps?

Or a link to 3, 3 gallon containers growing under the hps. What is the best amount of plants for this space? Would it be better to use like a single rubber made as a pot? This would allow more roots, but I'm not sure if it'd translate to more buds in this scenario.

I'm worried that a plant from a 3 gallon container might yeild significantly less than a container (marginally?) larger

Realize that once they grow, it will be the space for the branches, not the pots that will matter. I think 3-4 plants is your max (similar size to my grow space). I don't think that square vs round will matter once. What you gain in l x w you are losing in height and that counts for roots as well.

don't think it will matter once??

What you acquire in l x w you are losing in height "and that counts for roots as well" the goal of square pots its to minimize the length/width and make it so I can stack them in next to each other without having loss of space, as you would if you put two circles next to each other, as opposed to two squares. The circles don't go together uniformly as do the squares.

does anyone know the dimensions of square pots(3 gallons)