My personal highest has been 4lbs out of an 8x8 tent under 1280w. So about 1.4 g/w. Averaged about an oz per sq ft. Idk if thats high or low, but it took a lot to get that 1.4 g/w. I'm not saying it can't get higher, there is always things that go right and wrong in a grow, but sometimes things jus go very right and it soars above that expectation mark.
Vegged for ~2 months, multiple strains, 5 gal pots, scrog net, under 1280 cob watts. 4 meanwell 320s, different models -
2x HLG-320C-1400A
1x HVGC-320C-1050A
1x HVGC-320C-1400A
For a total of 20 cobs, (8 Citizen 1212's and (12) Citizen 1818's) mixed spec, but mainly 2700 and 3000k.
My average cost per oz, to grow 64 oz was $15.63 USD over 4 months.