You would be surprised at how well a 250w works, it's what i use and iv had plants just shy of 5 ft and the 250w was more than enough to handle them with no topping or any training at all, and im talking big dense buds aswell, plus my grow room height is 6ft tops, just a canvas wardrobe. Check em out in my sig. just thought i'd add im currently germing a dinafem blue widow myself just waiting for it to pop so il be keeping an eye out for this. Nice1