dont go by plants its how you grow them ive seen some one grow 5 plants under a 400w and get the same results as his last grow when he did 10 i think you get an estimate of up to 15 ounces for a 400w
ive grown 10 ith great success but am cutting it down to 8 and depending on the results might go for 6 prettymuch just bigger buds with fewer plants
try it you might get away with smaller plants but i wouldnt go over 10 personaly as i veg to 1 foot before flowering usualy takes round 4 or 5 weeks from clone