Keep 18-24 inches away, some of my leaves actually burned when I didn't raise my lights quickly enough 1 week and it was still a good 12" away from it. Don't bother with multiple CFLs for your actual grow, I tried one of those setups with 20 light bulbs and it was a hassle having to adjust everything as the plant grew. The one thing CFLs are good for are seedlings, clones and mother plants. ~100w split with multiple Y splitters per 1-2 square foot area