I am still new to growing, but feel my last single plant was a successful one. The only reason is because of the extensive amount of research I've done. I am using 2 4' fluorescent (plant and aquarium) tubes on top as well as 2 4' fluorescent tubes at the back, 1 4' fluorescent tube at the front and 2 13W CFL in the middle of 20 seedlings ATM. One plant has grown 2" in 3 days and has multiple branches and huge fan leaves. I personally would only recommend CFL's for the vegging stage as the HPS will give of a bigger and better quality in a quicker timeframe. Also with any light you want to make sure that you are able to move them 1/2 inch at a time. You may want to move your plants around as well and put the bigger ones on one side so you can raise just one side of the lights. It also doesn't hurt to have lights at the bottom of your plant as it will help growth. I am still curious to try tinfoil on the top of the cup with a 1" hole in the center. If anyone wants pics I can post them. Just have to get over to the "office" to take some pics.