This question is for the single plant scroggers :)...

you should get a similkar yield grams per sq foot as several plants, if in each context you make full use of the light. light = yield. maximizing photosynthetic potential is what we can control and genetics is a rising tide that lifts all ships (or lowers). ambient co2 50-60g/sq ft is definitely possible, but some genetics may not reach that even if well distributed under light. If it's a chunky monkey you might get to 800+grams in 16sq ft. -- less space for equipement or if light doesn't fully cover everythign etc etc.. space away from walls for breathing could cut into it. all rough estimates. With high efficacy lights can push 1.5-1.7g/watt. 480-540 watts with the higher tier efficacy lights all you need. As long as it isn't limited by other factors -- the pot size, fertillization, the climate, et al...