not much room for 4 plants you would probably only want to flower 2 plants in that size cab if growing from seed you might be able to start 3-4 and cull a couple once sex is determined a 150 hps would probably work well but if the cab is outdoors or someplace hot where temps will reach 100 degrees or better your going to have temp problems regardless of what light you go with if its inside an air conditioned house dont really see the outdoor temps even being an issue.