See this is becoming a bit of my dilemma these days as well. My DIY cxb3590 fixture running a Meanwell HLG-185h-C1400B cranked all the way up uses 104w at the wall per my Kill A Watt meter. I realize I could add 2 more COB's to this driver to bring it up to a full 200w fixture. But.....I feel I would still be leaving something on the table only driving them at 1400ma. The Cree spec sheet is based off running them at 2400ma. I just realized this over the weekend. I am torn between adding the 2 other COBs for 200w total with the 185h-1400 driver or to up size the driver to a HLG-240H-C2100B which would give me a 151w fixture with my current 2 3590's or 226w if I add a 3rd COB. Cost wise it's $80 for 2 COBs or $70 for the 240H-2100 driver.
I have finally broke out of my little grow cabinet and am set up now running a 28"x53"x78" tent with a 4'x4' tent sitting here to use as well. Right now I have my old MarsHydro 300w(174w at the wall), my DIY Cree cxb3590 fixture(104w) and a brand new Amare Solar Spec 150(163w) that was generously gifted to me from A-Train via Amare as the runner up to the 2016 Yearly POM Champion contest.