Enuff light??

plan on upgrading flowering room to 8x4x7 from 4x4x7. currently have 600 watt hps as of now. was wondering if I can get away with just adding another 400 watt hps or 600 watt hps and have enuff light for my setup? also was wondering what setting I should have my dimmable ballast set to? and what am I using to determine when to turn it down or up? sorry if its a newbie question but that's exactly what I am..thanks for all help

2x 600w would be fine, each should cover a 4x4 area no problem

thought that would be good enuff..just better safe than sorry. thanks man. oh do u know anything about the ballast question I asked?

100% for both for maximum coverage and penatration UNless hear is a poblem

Unless heat its a problem*