DO you have any idea what it takes to get 4 ounces a plant? Seems probably not . Yields on plants are strain specific , dependent on growing style , and amount of light . Your not gonna run a 600w with 20 plants and get 4 oz a plant, sorry . To get 4 zips a plant off of 12 plants you would need around 2-4000watts of light . That's also if you know what your doing a and have a high yielding pheno . Then with all those plants and light you also need a huge dehumidifier , massive a/c and lots of other equipment. Not as easy as peop[le make it seem .