With only red and blue, it is not possible to provide enough total radiation to larger plants without bleaching the top leaves. It's like trying to cook a 2 inch rib eye steak with a hot cast iron on the highest setting the whole way through. To get enough total power of just R+B, you will fry the top of the plant while leaving the center raw. Most people gave up on the Red + blue only fad years ago. It actually is more complicated than just hitting plants with their 2 favorite colors. White has been proven to be way more effective with just about every journal I've seen. I've never seen a R+B grow and been thoroughly impressed by the results.
Obviously a lot of people have tried the failure combination of red+blue. It didn't matter how much R to B was included, white always yielded more.
I think what you are doing is using logic to prove your conclusions here, which works most of the time. I used to think more R+B was all plants wanted and kept trying to tune my spectrum accordingly.
HPS spectrum is actually really good for producing marijuana flowers. It's not just bombarding the plant with photons, but its also a better spectrum for flowering than any MH of the same intensity. That implies it's the spectrum of HPS that's so special.
R+B only grows always end up behind schedule, and yielding very little.
IMO, HPS spectrum should be emulated, not avoided, until it can be beaten with something that produces better results.
As long as you have reds and blues in sufficient amounts, which a regular HPS has, the plant doesn't give a hoot..
