Need help with lighting!!

ok, so i have four plants in bubbleponics, all auto. Sweet dwarf, 2 afghan kush, and a la diva.
Would it be fair to say that a 150 watt hps over all four plants would produce 2 ounce per plant?
Or would I hve to add a second 150 watt hps?

at least a second 150w

If you got 8 oz from a single 150w that would be well over 1g/watt, and that is simply not going to happen especially with autos.