This is my opinion from my research and what I am seeing so far in my own veg tent and the flower setup that is currently vegging a big sick plant as well.
These plants respond well to less current per COB (driven softer) and put closer to the canopy......running them bare like this for veg gives a nice spread and is a good combo with the softies.
Then you have the opposite end of the spectrum. Run them hard as all get out and put them up higher with good optics. I figure the guys building lights have done a bunch of R&D so there's really no wheel to re-invent here right now.
I just took down the window venting for my portable A/C that's how much of a difference the COB's are making in my room. I live in a hot and tropical environment too so no winter snow fall colors etc here.
Your head can spin man but the good thing is when you do DIY if it doesn't please you change it. Or just run different setups and test them yourself.
There's just so many different variables that need to be taken into consideration and often are not is all. We need to help people get back on track growing some dank ass plants and stop arguing over a percent or two in efficiency that is all within the margin of error of any tests.
I myself am trying a certain HID mentality if you will with my K temps/color choices. For HID was Blue MH for veg then HPS for flower (ie: RED) So I chose 5K for my veg tent and 3K for my flower setups. I will aslo test in the future some plants beginning to end under each as I am told the 3K has "different" growth characteristics.
However, my quest is also different than most. One part no one really talks about is cost effectiveness. So I set out to build an LED that was on par cost wise to my platinum 1K ballast and bulbs for my Eye Hortilux HID's. IF I have to spend more and run watt for watt I do not see the advantage for me as a "home grower" aside from the heat and less noise etc. BUT, I can always hang more lights if I need to as well and it spreads the cost right?
Sorry just my $0.02 and rant over. I am no expert and have made many errors as a new grower but try to learn from everything. This was my second DIY light, and if it keeps going as it is there might not be anymore HID here in the MOBO garden.
You need to have a solid plan going in or you will just amass a pile of parts as you change your mind (ask me how I know) lol.........
Keep us posted I want to see this running and growing plants
Cheers!