Yea supercropping is preti much bending the stem over so kinda like the fibers inside the stem snap without actually snapping off the branch if that makes sense lol...
Apparently a supercropped branch when it turns back upward by itself it grows thicker than it would if just LSTed so it can support more weight as by snapping the stem it kinda tricks the plant into sending loads of "Auxin" hormones to that branch (tricks the plant into thinking that branch is the "top branch").
All in all it produces a larger/thicker stem for a lower branch that would normally be lanky. It wud probably be good for the type of grow you are doing but choose a method that works for you
As for yield I know for sure that indoors 600watters are very lumen to watt efficient and put out less heat than 1000s and I know it is possible to get like 2lbs+ per plant as I saw 4 600s over 3 plants that were FIMed (a kind of topping) and pruned alot throughout the grow (lower growth cut away aggressively), vegged for 8 weeks in 60 litre pots grown in coco and yield was over 6lbs dry. To achieve a yield this big
indoors the main thing is space as the room these plants were in was 6 metres X 4 metres and those 3 plants filled the room from wall to wall and were up to the roof (8 feet tall).
A closet sized grow is pretty restricted due to space but I guess 8 Oz on 1 large plant would be considered a large yield in a closet your size.. Possibly done in a SCROG with a 400-600watt HPS. Just gotta use all the space you got to your advantage