if your talking about 10x20 and your gonna use like all of it? well then id say do the 8 1000w's if your really gonna need that much but thats like 16 pounds a harvest with a good strain, id go with the above recommended, get 2 1000w hps's, and then also get 2 1000w mh conversion bulbs, use the metal halides on 18/6 until plants are ~3 feet high, then switch to the hps on 12/12 until trichomes are to your liking, get a gigantic canfan with a big filter to stay off the radar, and cool tube those 1000w's with it also:thumbsup: