Yes you can yeild 1oz per plant with a 250hps. I yeilded a QP with a 150watt hps and 4 45 watt cfl my first grow. Under the same lighting I grew out a skunk 1 clone that yeilded 22 gm. Its not about how much light, but how you use the lighting. Cool that 250 as much as possible and ventilate good. You should be able to get the light withing 6 inches of the plant. And reflection reflection reflection.