Hello,
Your plants are looking very good so far, they're in those last maturing and bulking weeks now. By the looks of the whole plant you've still got a couple weeks to go. Let the majority of the white pistils change to orange and shrivel up and you'll be closer to being ready to start the flush.
I see some amber trichromes coming in already which is great.
I'd say continue feeding them nutrients at a modest level over the next couple weeks until you see 60% or more of the pistils colored and then i think it will be time to do a small flush, maybe just a couple days. Personally I think plants who haven't been overly fed their whole lives don't require such a long flushing time, but i do notice a good change in bud quality when i give them at least a 2-3 day flush.
Just play the waiting game for now and you'll be trimming buds in just a few weeks.
Happy harvesting. ✌️