Hey there CC - stopping in to see your ladies. Looks like you are getting close to harvest. woohoo
I usually wait till I see some amber (10%) or so on the trichomes that are on the buds - don't worry about the leaves. On the yellowing, don't sweat that too much unless the plant yellows from the ground up = nitrogen deficiency.
That one big bud sticking up above the others, whats going on there is the plant is using the stored nutrients in the leaves. TO ME - when I see them still standing tall pointing toward the light they are not finished yet. The yellowing will continue and at some point
soon those leaves will be spent and the plant will discard them. That's the point where I start watching closely.
You can harvest anytime tho but I like to wait until I don't see much new pistols and there are a few amber trichomes. This is the time where the buds will fatten up and they get that energy from the fan leaves. Not all plants do this but that one tall plant looks like some of mine in late flower.
That plant is ripe but you can wait a bit (up to a week or so) and just water a little and wait till you and the plant are ready. I usually wait until there's no rain the next few days so when hanging to dry its not high relative humidity so I don't hang my buds then have mold issues or have to worry about that. Once the plant is chopped it has no way to fight off things like PM and such.
Patience is important if you want a good yield.
You're doing a good job, don't stress on it mother nature is doing her thing, sometimes best to just watch closely..... let the ladies tell you they are ready. It will happen.
Example of what I'm talking about right here. See the leaves yellowing and getting ready to fall off and all the new white trichomes.. I'm letting this one go until those trichomes stop coming or mostly stop. It won't be long but I don't care about the fan leaves at this stage. They are giving up the stored energy while the buds are getting bigger. We can expect +30% yields at this stage with a little patience.