The top layer of leaves is not the same as the lower layer.
Anything green on the plant can probably conduct photosynthesis, but it's a fraction of what occurs from mlight hitting the tops of leaves. This is a fact that is beyond debate given existing knowledge.
So, intercanopy lighting can help. It'll help more of the light hits the tops of leaves that are otherwise shielded.
Same rules apply. Don't want to be aplying more than ~35DLI to a leaf surface. Blue wavelengths promote more branching, Red wavelengths promote more stretch, but that is all relative to genetics. You cannot turn a bushy plant into a lanky bitch with red lights. Too much light can still stunt growth. Rules do not change based on the vector of light.
Same reason why it's a myth that people think removing a leaf to allow light to hit a bud site is a benefit. Their was greater benefit in the 100x more photosynthesis taking place on the leaf surface, lol. Products of ATP are not restricted by where it was produced. The contents of the pholoem freely flow around the plant and apical dominance dictates where it is used most.
i've never seen any data on light spectrum causing greater trichome production. Without real evidence, you should be skeptical about such conclusions. Some hypotheses can't be answered with 1 experiement. All require verification. Something simple like - does the mineral contant change? - is easy to measure and calculate, so you can be really confident in 1 test, i'm sure there are more to verify it, too.
Having some foundational knowledge would have helped the community not fall for so much bro-science. Reading what some people believe is absolutely hilarious and depressing at the same time. In a world where so many are anti-intellecual and anti-science, this is not surprising. Turns out reading and learning math is useful, lol. Don't trust the mob. They struggle with fractions.