lighting question.

[phil]

Ron, New grower here, lighting question. I am going to be using the 11 plant system, basically 4 1/2' x 4 1/2' enclosure-topless for the lighting. i have 1- 150w hps light and 2-400w MH lights. Do I need this much lighting?-will it help my yield if I use it all? I want as much product as possible from my plants. Does the amount of light add to yield? Basically- are the two MH better than using just one of them? And these are the types of MH lights used in factories and industry. Since I am leaving it "topless" should I also use a fan? It will be in a basement where it can get pretty cold if the temp. gets low. How much light, what about the heat? Please help. phil.