im back , I started with 2 400 solar storms did not have good luck on my first grow , but I got much better .I tried 1 light over 1 plant it put out 4.6 oz on one plant , did very well . now I tried something I put both of them on a light mover same plants same soil coco and same fertilizers my room is 7foot by 8foot the only thing that has changed is the mover . that same plant only this time I had to let it go for 12 weeks ,all the flowers were less than half inc long not good, but in a different room same thing I have 2 400 watt hps lights I got 6 ozs from one plant .I wish I had never bought these lights , I wish I could get rid of them .
He may not be using the *whole* room for 2 plants but we tried to help him with his "journal" months ago and he bailed in the middle. I don't think it matters at this point, I think he's made up his mind and done.
I prefer to judge by grams per watt too but that's another story...
Disclaimer: I still use HID and I'm NOT an LED expert. All of my LED knowledge is from other parties or research so I can't say from first hand experience one way or another. I also run a medical grow consulting business in SoCal.