how many, SOG, 150 watt?

Hey guys, so im tired of the cfls, and im gonna get some money soon so im thinking of getting a 150 watt HPS for 84 bucks with shipping. i have a very tall closet that i filled with plants once and grew under a 250 watt no problems. I wanna grow in half of it with a 150 watt and SOG it. i wanna fit as many plant as i can under the 150 watt. heres the plan, im gonna veg till they are about a foot high and then 12/12 it so they get 3-4 feet high. i was thinking 5 or 6 plants what do you guys think? im using FF fertz and MG organic soil. ill have a couple fans too.

i have the mylar ready, but it wouldnt be just the 150 watt but also about 150 watts of cfls too placed around the plants. maybe ill just do 3 or 4 plants.