Maximization!

Most ppl use or say a area of 4x4 or 5x5 ect.
Does it really matter if its a square?
For example, i was thinking about setting up a rectangle area of 4x12. Using 3 1000w hps for both stages after transferring from T5HO's.
Is "being square" in this situation better?

Any tips <lighting, circulation, 1 vs 5 gallon pots>?

Lights can go about 8 or 9 ft. high. 6 in. air cooled.

That will cover 5x15 perfectly.
Pot size depends on plant count and size.
I prefer fewer,larger plants others prefer more smaller plants.
Both have pros and cons and is something you should work out via experience.......try both and see which works for you.

I guess i never understood why ppl put a foot tall plant, in a 5 gallon bucket. Doesn't make much sence to me.

No it does not........or grow a five foot tall plant and trim off the bottom three feet.