USE the best 600 WATT HPS lights you can find

Also you might look into using a track

It is also true that the 600 watt hps system give you the best watt to light ratio. The new bulbs have a fair amount of blue and do a decent veg cycle. I used two of them in tandem in a 7' x 4' space and got great results. I did my veg cycle under fluorescents however.

GL