How to approach harvest.

It’s mainly CBN btw CBG is the mother cannabinoid to all the others.. rare to find any in a mature plant unless it’s been bred that way. CBG turns to all the other cannabinoids as flower initiates

I agree with Ezzjaybruh...

This is very subjective, most will elect to chop the whole plant where some will chop what has ripened more and leave the rest to finish off some more, up to you. And how consistent you want your bud to be. Some more CBG(couch lock) leaning flower or a mix.

Personally I’d just chop all at once. I don’t think you’ll notice much in smoke between the lowers and uppers. You can separate the lowers and keep them separate so you know which is which and see if there’s much of a difference.. cuz frankly I did a partial harvest like you’re suggesting a few times when i started out and it was not noticeable really.. not enough to be worth separate harvests, so I haven’t done it since