Answer: Don't worry about it. Pot growers typically focus on all the wrong details. You have to start with nutrition. Absolutely nothing else matters until you get nutrition figured. Then you can throw as much light as you want at the plants. Literally. Every single aspect of growing starts with nutrition. Everyone ignores it. I've not seen an off the shelf fertilizer or soil recipe yet that let's you take advantage of high light intensity. Grab any high end grow light. Grab the best bottled ferts. Try running the light at full power. Your plants will get purple stems. The tips will turn white. The yields and quality will suffer. The solution is not to come up with some arbitrary light intensity target, the answer is to fix the crappy nutrition. There's more to it than Nitrogen EC and
CalMag, and none of it is arbitrary or subjective.
I promise you, the guys who hone in on the mountain of acronyms in pot growing and ignore the basics of nutrition are not growing amazing weed. They all dim the lights hanging out nutrient deficient plants. Light burn and heat burn are not a thing with Cannabis. Purple stems is not protecting the plant from light, it's begging for proper nutrition. There's much more to fertilizer. It's straight crackhead activity to worry about light science after paying for pre-built lights. The people who build the lights are the only ones who need to worry about all that shit. You don't need to be a freaking light engineer to grow pot.
Does every single person who drives a car need to know how gasoline is refined? The aerodynamics of their hood? The composition of their tires? No. Only top fuel drag race crews need to know how to know that shit, and no where near the depth of the manufacturers. And I promise you are not at that level in pot growing if you completely ignore the science of nutrients as almost all pot growers do. I see it every day, "light burn, turn the dimmer down" when all it is, is nutrient deficiency causing light sensitive as a side effect.
Learn nutes, pot growers. First and foremost. I've grown my entire life, started outdoors, no dimmer knob. The idea that people need to regulate indoor lighting is absurd.