grams per sq ft is best to describe yield
grams per sq ft per day is best to describe productivity/ efficacy.
you can have a 300g plant but if it takes 25 weeks, that's shit. With a 5-6 week vege i want about 150-250g per plant and genetics is mostly the key there. I want to average 50g/sq foot or better. If i doubled the number of plants and shaved 1 week off of vege, i'd probably do better with grams per sq ft per day, But, that comes with more effort with transplants and all that jazz. Even so a grow cycle is roughly 100-105 days. so about .5g per sq ft per day. This metric would be the real dick measuring metric. Time is a primary factor.
1 big plant that takes 5-6 more vege weeks is just costing you money.
maybe, i'll go buy 24 2gallon pots and try it some day... i'd want to average about 85grams per plant. 4-week vege would do that more times than not. 100-105days turns into 86-91 days. And, that's up around .58grams per sq ft per day. 16% more efficient production. shave 2 weeks of high watt use off... win-win.