I only ever weigh mine just before there jarred so i know exactly what iv lost in curing, i always get the same result.
I genuinely do think people weigh there bud wet on this forum though because some of there "6-8oz" plants look at least 50% smaller than my 6-8oz plants.
Yeah if your after yield get as much light as possible, talking about over kill lights, i run 3 600w hps lights in a 4x8 area, the reason i do this is because if my trained plants arent enough to produce as much bud i know that the light will help in aid and just push me over the edge for it, the most iv gained from the 3 lights is 47oz and that was with i think around 6-8 weeks traing, 8 total plants.
I find i grow better and more quality plants in a 4x4, less area and more time to control the environment as thats just as bigger factor as lights, i do think you can tackle 20oz for every 4x4.