Right but if you listen to all of what Bruce is saying, the first thing he says there is that an ideal spectrum matches the sun - the sun's spectrum has oodles of green. The second thing he says is that adding green led's is inefficient but we're not adding monochromatic leds - white led's are just blue led's with a phosphorous coating so nothing to worry about there. Bruce then goes on to explain the benefits of green for light penetration to lower canopy.
It literally all matters though, some things just matter less and some things just matter more. Will a mixed spectrum LED grow dope plants (Black Dog, Kind, etc)? Yes absolutely. So if you as a consumer want to shell out more money to buy a light that has lower PAR output (and if you don't know what PAR means or why that is important to plant growth, look that up) but will consume more electricity while producing greater heat to get the same job done; go for it - you'll get good smoke and pretty buds, that much I'm sure. I'm not trying to sell anyone on anything, I build my own shit and I have been for the last 6 years. Y'all are welcome to believe what you want, there is enough evidence based science out there for anyone willing to look.
First let me say that I agree with a lot of your statements and kudos to you for building your own lights. What I can say is this, yes green light matters and is in fact photosynthitaclly active contrary to what light manufacturers previously believed. but things should be taken into context.
For example, my next grow is going to be 12/12 from clones, I'm shooting for a very short stubby plants with each one having one big bud at the top. In my case, I could benefit very much from the blue spectrum to keep my plant height in check. I don't need green that much as I wouldn't benefit from canopy penetration for such small plants. I need much red because as I understand it's the most effective for flowering and I need UV in order to stress the plant to produce more THC and Terpenes . So in my particular case, a spectrum that resembles BlackDogs will be the optimum for me. Now if I were growing large bushy plants then I would certainly benefit from the green color penetration. Although those light strips are lacking in UV and so they need supplemental UV.
Lastly, yes it's true that these light strips with full spectrum light produce more umol/s/w than monochromatic LED lights but this figure should still be weighted against the plant spectral response to arrive at which light is actually more efficient overall for plants. I'm not a scientist, and if the scientists themselves are having a hard time determining the best light spectral distribution for plants, then for sure I wouldn't pretend that I know better.
Lastly, in a future trial, I will try using normal 4000K LEDs (not grow LEDs) and I will supplement them with UV and Red and I'm pretty sure they will work great actually.