Your instincts are spot on. Start the flush with next feeding. Only PH water to the PH you’ve been using. Typically indoor with nutes in soil 2 week flush. Coco 1 week or so and hydro is a few days to a week as the plant intakes at a different rate.
Don’t change anything else to the conditions. The plant will change how it’s it producingthe air inside so expect changes but don’t freak out. Just watch the humidity to ensure no Last minute mold.
They look good! The added amber hue from the trichomes should add that couchlock or body response. The later in the harvest the heavier the high and body feel as youre basically aging the trichomes. The earlier can cause a more uplifted mental high.
I learned two intersecting methods both of which do not begin until minimum 8 weeks from flower flip.
First the buds in top canopy should have 3/4 turned to red hairs which then turn brown in the harvest window.
Second is the magnifying where you view the trichnome on an angles so you can see through the side of stem.
Is it clear like a icicle? Or milky cloudy?
Do not be fooled by the tops as they reflect and look potentially cloudy from the wrong angle.
Harvest window is two weeks so relax and don't chop early, but a late harvest is counterproductive to thc and switches to cbn a sleepy less happy buzz.
Your hairs look like they have switched to brown and your trichnome is still clear so I think it is perfect to flush it