You can do amazing things and boost yield, however IME highest GPW will be achieved with 1Kw lights. I have seen great results with 750's as well. I have flowered with 600w's also. Lower than 600 and you are just a cab / micro personal grow.
If you double your GPW and use half the power, you end up with the same yield In this game we are always trying to increase total yield irrespective of expense or time involved
If you double your GPW and use half the power, you end up with the same yield In this game we are always trying to increase total yield irrespective of expense or time involved