i was thinking a similar thing i have started a thread in closet growing keep an eye on both threads i was thinking 50w per tube, my dims are 2'x4'x6+2' with 4 on each 2' side and 6 on each 4' side thats a total of 1400w for me (400w hps) which is around 175w per square foot i personally think thats a hell of alot of over kill though