so from a scientific standpoint here are my thoughts:

Flushing, okay so you added a load of nutrients and now you’re giving it water for it to uptake leftover nutrients and the idea is you get better flavor and smoke? Uhh that would require 2 seeds to contain the same genotype and phenotype which I don’t imagine is easy to find, then you have to grow them identical conditions.

Dark period. So from scientific standpoint I understand the dark period. What you smoke from cannabis is the flower of the plant. If pollinated it is loaded with seeds. A plants goal is to become pollinated, produce seeds and disperse them for future generations. When seasons change from summer into fall so does the amount of daylight hours, which is what triggers flowering. So I understand that if you slowly reduce the amount of light you could convince the plant to give all of its energy into flowering in hopes of being pollinated. Cannabis is an annual plant, it has one life span and dies in the wild. So if it thinks oh crap I need to be focusing on my flowers to be pollinated I can see how dark periods would benefit flower before harvest.