You can use as many lights as you can fit it your growspace, the more the merrier, although you do have to consider heat build up, even cfls produce small amounts of heat, and several of them in a small space can raise the temps somewhat, you want to keep it below 90 really, I believe growth slows then and stops around 95 (obviously this is dependant on strain) also lows shouldn't be below 65. A thermometer might be worth buying if you suspect it may be getting near or past these values.
Miracle grow is a common bone of contention on this site, some swear by it, others swear about it, I have never used it myself, but a friend once grew a plant to over 7' tall outdoors using garden soil and miracle grow, it yielded around 8oz as i recall, but even flushing with water for 3 weeks before harvest, and after curing it for a month it still tasted like shit, REALLY harsh with a mild body high. Grew 12 clones from that plant, taken very early in flower (as soon as she showed her sex) indoors hydroponically, finished 2 weeks later than its mother, and was an amazing smoke with a bit of an uppity high, then a real couchlock if you smoked more than a couple of grams in an hour!
Sorry I do ramble on a bit when I'm baked... 5 points if you can spot a point in that /\
I really think cfl's could grow just as well as a bigger, more expensive light, provided you have enough of them, and of course they're more efficient so I'm sure they will treat you very well! once again good luck! Also if you felt like selling some of your stash you could invest in your grow even more if you felt the need to (maybe not)
