I keep all of my panels as high as I can get them. I have plants that are from 3 feet away to within 6 inches of the light. I will say that they dislike being iwthin 6 inches. i would try and make sure you are about a foot away or more from the panels or you may see some light/heat stress. I get fairly solid buds on most of my plants all the way to the bottoms. I have a 7 foot tall tent with pots that are probably 12-14 inches tall.