hi 2legit,
I have a hps1000 and i keep it about 16-20 inches from the canopy and that seems ok. My light is air cooled, so if yours isn't, you might go a bit higher.
the rule of thumb is - "hold your hand under the light, and if you don't feel discomfort, then neither will your plant." This might work for some, but my plant's were getting burned even though i thought it was ok.
the closer the better, just not too close.....