I think you are on the right track. It also depends on how you plan to cool the room. Keep on mind, the more light, the more c02 your plants need. //as long as the girls stay cool they will grow to be everything you hoped they would. Might be a little over-kill, but better to error in the side of monster buds ReD <I>
<>
p.s. Here is a pic at 4 weeks under 1000w hps only grew 3 N.L.X. plants and yeilded about 3.8 oz at weeks 12
good luck