What I have said and still maintain, is that the optimal intensity of light would be somewhere in the ~410-600 umoles range for the entire plant, not just the canopy. Bubble wrap your plant in warm, gentle light.
No, a quick search for ~400umoles shows that you have said:
Target for ~400umoles as uniform as possible.
That is where the ~400 umoles comes from. It is the amount needed to maximize the rate chlorophyll can perform photosynthesis.
an accredited university which happens to show a chart where the photosynthetic rate increase peaks ~400 umoles.
The documentation I have referenced finds that photosynthesis has a saturation point at ~400 umoles which if applied to an entire plant would have the potential to reach optimal photosynthetic efficiency.
DLI is what we should be using. 18-25 mol/d is a good target. (which is 400 to 600umol/s/m2)
It's also in your avatar for Pete's sake.
You even said that adding more COBs to create a PPFD of 600umol/s/m2 would give you the same yield as 400umol/s/m2.
Over and over and over you keep claiming 400umol is the maximum that a plant can usefully process. Sometimes you cop out and admit maybe up to 600umols might work or you add some vague nonsense about "whole plant" needing to be in the same light, but clearly plants can go well over that and even up to 1500umol/s/m2 with increasing yields. There is no saturation point at 400 or 600umol
The Chandra chart was based on tests on leaves. A single leaf having more photosynthesis with more light up to 1500umol/s/mw also. So you cannot hide under your "the light goes through to the other leaves and creates 400umol there". If you had ever grown cannabis plants you'd know this is nonsense BTW
Which brings me to the other claim you make:
1. Find the saturation point of your plant.
If you look at the charts, aiming for the saturation point is daft. Everybody picks a spot on the curve where the efficiency starts to come off the straight angle. That's what professionals aim for. Not the maxium light level that the plant can handle. Which would be 1500umol/s/m2 for Cannabis plants.
In fact people tend to aim for half the light of the saturation point. So based on your holy chart of light response, 200umol should be your aim for maximum efficiency