I was told by numerous people to put the flouros 1-2inches from the plants. I never burned a leaf and had them on 24/7 for one full month before going outdoor. They were 1ft-1.5ft at 4 weeks old and had tons of nodes(very bushy).

I used the 40watt cool white bulbs with 1 2700k red bulb in a 3:1 ratio. Worked very well. I plan on using the 125w 6500k and 2700k flouros on ebay when i do my indoor grow. The bulbs are fairly cheap and they produce 8,000 lumens. Also saw a 400w hps setup on ebay for 99 (bin) +40 shipping. not too bad.