I keep my 250 HPS (with a heat shield) about 6-8 inches above my plants and they dont get burned, if I had a fan blowing over the top I could probably get them closer. My veg box was going to be 2 1/2ft tall, I would be using cfls so they could get realy close. What I meant on my question about the veg box was if the base area should be smaller in the veg box?