I have never even come close to a gpw in a flat grow.I don't remember exactly what my Las flat grow was about 2.5 # from 2k. Jump to vert and I got 3.5 # from the same 2k. Probably could have hit 4# if I ran bare bulb.I don't think anyone is hitting 1 gpw with out serious training. If you run 4 plants per sq. Ft. Sog style probably the easiest way if you don't care about federal mandatory minimums. Mabey if you run big bud or some other high yeilding strain. Them problem with that is that those strains tend to be low Thc. You won't hit numbers like that with most ogs. Sure you got a pile of nugs problem is good luck getting rid of