Don't know if it helps or not because I have only one grow under my belt, but I had my seedlings under a dual 400W HPS/MH hood from day one. I kept the lights about three feet from the plants though. I ran roughly a 12/12 cycle for the first week or so, then I went to 24 hours a day of constant light until I started flowering. It worked well for me, but I suppose it could have just been beginners luck or a really hardy strain of weed. I believe my plants are indica, but because they came from bag seed I am not positive. Good luck...