A good way to see if the lights are too close is to put your hand on top of the plant for 20 seconds or so. If your hand feels uncomfortable - the light is too close. Easy. You can usually get cfl's very close to the plants (closer than HPS or MH) if you have a decent fan in there. Dont worry too much about the plants getting windburn - I have a 12 inch fan that sits about 3 feet away from the plants and usually its on high speed. The plants next to the fan will adjust by building a strong stem. If you want to keep the plants short just make sure to flower them when they are about 8 inches tall. You can also try LST (training) or topping but these techniques will make the plant wider - I dont know how much horizontal space you are working with. It is easier on the first grow to just flower when they are short and dont worry about training.
The goal is to get the lights as close as possible with the temps as close to 70 as possible and flower early. Peace.