The 400 works great! 600 is better though. A 400w hps is roughly 50,000 lumens, and a 600w hps is roughly 90,000 lumens.
Yeah a 400 would cover 3 pretty nicely. 600 would be better though.
I wouldn't bother with the cfl. In order for it to be effective it has to be real close and when i say close i mean close, like within 1". Now you don't want that cfl blocking the beautiful rays from your hps do you? Your 400w hps would have more lumens to the plant at 1 - 1½' away then a cfl would have when it's pretty much touching. So i say the cfl is a waste.

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Hospitals have patience... I DON'T!!!