I personally dont see a need for 350 at all with COB. Unless you can get them dirt cheap. Still prefer 1 COB a sqf at .7
With how my narrow my footprint is I could have gotten away with 4 cobs in a straight pattern at 1050 but I didn't like the idea of the look or the walls reflecting even less light (added distance to wall)
Just wanted a super efficient panel and uniform light (more sources, dont typically grow 'Xmas tree style') and use the crossovers for my intensity/blending (reds incorporated)
Sure it cost me for it, but i wanted the best of the best at its best... (Apache tech fever much..?)
Girls don't seem to mind it and still leaves me plenty of headroom to throw down intensity equivalent to the sun/higher than my sq200 can measure, if I decided to kill my plants slowly lol.
All application/user specific
I'd vote 1050ma, probably my next venture for my 3x3', dimming won't be an important feature for that area (all white, plenty of head room)