For the bulbs you have, you can keep them at a distance of 4-5 inches. However, those reflectors you have can trap heat and aim it at the plant. I've seen that first hand. If you feel like heat is being trapped from the reflector, you can remove them. Light from a CFL bulb does not get reflected that well anyway.

I like bronc's idea about the T-5's, if you have the money to buy those. :stoned: