just do not veg to long 
that was my big take away
I did 108 six inch square pots in soil less
with 3 - 400 watt lights 2 hps and 1 mh my first run I vegged too long 20 days
second time I did it only vegged for 10 days then did the 12/12 for flower
painless to do 1200 grams a run, but for me the plant count was too high
all the best
Dequilo