That should be fairly easy to do if a man has experience in filling his space correctly and growing in general.
I don't use the 550 but I do use 2x 260w kits giving 520w and 570w at the wall, just looking at the figures they might be slightly higher on the umol/joule. Which puzzles me somewhat considering they used to be $285 per kit (now $325) which is cracking value in comparison to the 550.
Anyway my best with that side of my tent is 956 gram dry (4 plants per 4x4) which is 1.67gpw or something. Im Talking what you guys over there call vendible
I was hitting 0.7 on average with my 600s.
But that makes the lights sound like miracle workers and there is more to it than that.
I used to run 3x 600 hps in a 4x8 and run 3 crops staggered. When I switched to first cobs then also QB kits I also increased pot sizes, switched to cloth pots, reduced from 3 crops to 2 crops which allowed me more veg time and did more training, mainly the addition of more super cropping and staking some of my colas horizontal to further fill my space.
When I was running HPS I could of fitted a plant or two extra in there but I didn't want more than the plant count I had, so I wasn't running my space to its full capacity. I also used cooltubes so I factored in the reduced foot print and had space wasted.
Overall I would say that since switching to led I have made more efficient use of my space been wall to wall but with fewer plants where when running HPS I was been very inefficient and I'm not talking electricity. I also increased my effort as a grower and stopped been a lazy bastard.
Anyway dude I only hit reply because I saw you talking about using LED yourself and was surprised, I cant wait to hear what you make of them.
Always enjoyed your comments
P.S next time in the states I will pop round for the hand job.