All I know is the best meter we can use afaik is a quantum meter to get the most accurate representation of photons in each spectrum. Intensity is the most important followed by spectrum IMO. and spectral effects are absolutely a huge deal and not something to be left out of the equation. Including the rario of spectrum in relation to eachother.
the thing is once minimum spectral requirements it's all about the intensity . sort of like vitamins . you dont get bigger on proportion to the more you take. they meet the minimum requirements and then the rest are expelled. 2 lights the same out out both with different spectrums as long as they each have the minimum amount thr rest is about volume. doubling the par rating will do very little more . it is the same with the sun . it has a particular spectrum in the spring and summer but growth is similar. even the footcandles . there is 15000 +
or 150000 lux on a bright day but we don't have plants significantly bigger than normal. size is also extremely relevant.things just dont double. they move in percentages relating to plant size . +/- 1
or 2% at a time . those crazy adds that say DOUBLE your harvest
or EXPLOSIVE growth rate all fake terms that are meant to appeal to inexperienced customers. if a product adds more than 5% to your yield it means your were not doing some thing else in the first place