@sanguine
Sorry it took a bit, but here are some pics of the lights and a little explanation of what I was thinking. A lot of the thought process was inspired by the fantastic led/cob discussions here.
After reading that 3500 is enough to get through both life phases but hear many people supplementing I decided to do what you have done get some on both sides of the the spectrum and try to use the overlap to really get both ends better than just the 3500. So although it's four lights per rail I imagine it's just one dual spectrum cob
I wanted the power to not fall short so that's why I went with the 2100 driver with dimmer. I wasn't sure of strains or if I might run photos so I really wanted the ability to push 150w per plant if it came to it.
I picked up the parts from Rapid as it seemed to be the easiest way and the free shipping and discount worked out well. I also grabbed a 100w hobby kit with 4000k Veros and was very impressed with that.
To mount I literally just used .125inch wall 1" by 1" angle which was very stiff and held everything perfect. The pin heats inks provide a fantastic sturdy platform to mount to and come pre tapped to mount to. Couple wire ropes and ratchets and they are up.
So far I have been following height recommendations bard of people running the single 3500 and I think the 4000 I could probably drop the voltage a bit. I ran four plants the first four weeks of life under just one rail at about 60 watts (basically 15w each)at 30" and had no stretch. I then bumped to 100 per rail ( 50w each and 25w per cob) and they have grown as you see them. Bumped this week to 150 per rail and anything higher they get mad. All wattages are at the wall, with cheap kilowatt meter. I have a Northern lights and a FB GG4 behind these and even with the lights at 36" and less wattage they are shorter with super tight nodes do I am definitely going to have to manage overlap. Honestly at this ping in going to do the next run with lights off over the newest two plants to see if the extra light is enough to get them through four weeks healthy with good size.
Sorry for being so long winded, and that's straight. I try not to write stoned. Not enough bandwidth