i agree with silicity....u could push for 4 but density and light penetration to bottoms will decrease......i run all cfl's now, i have 3-4 above and i also put 2 on the door to the closet to help get more light to lower plant parts, i could show ya pics if u want....go for quality over quantity. u could grow 2 killer ladies under all those or 4 ladies that wont be as dense or budfilled....all up to u tho. best of luck
DDM