I agree. A 42 watt cfl would be good on top but adding side lighting will help with growth and bud development. The more the better as long as u can keep temps low. Also using white paint or mylar on the walls will help. Keep us updated on your grow sutto.as much as possible without compromising heat, that is the honest simple answer. More is better but to hot is bad, so start with 2 X 42w 6500k cfls and temp meter and work it up from there. good luck.