Ready to Start Flush? - Trichome Pics Attached

[adk10000]

Hi Everyone,
Second grow is coming to the finish line.
It's a 2x2 HYDRO closet grow.
Strain is Nirvana Northern Lights
Currently on day 53 of flowering since flip to 12/12
Breeder says 9-11 week strain. But some say this strain is ready in less than 8 weeks.
I'm planning to flush with Clearex and RO water ONLY - please confirm that I should not be adding hydroguard and/or calmag to the flush.
Also, for the Hydro flush, I have read 2-3 days is sufficient, but I also read that longer is better.
I'm planning to flush for 4 days, with the last two days being in complete darkness.
So the big question is, based on the trichs, when should I start the flush. The darker trich pics are from the top cola, but the canopy is dense and the lower buds are not showing any brown trichs yet.
Thanks for any thoughts or input!

 

[Cronk]

need to know as well

 

[RagWeedDWC]

I do not like a couch lock stone, so I harvest when the trichs just start turning milky, where you gauge this at the top or a little ways down is your personal choice and experience, if those were my buds and its at the top of the plant, I would wait a week and start the flush. If you like a more "stoney stone" then wait until its about 50/50 amber and milk.
I flush for 4 days same as you, but from prior experience do not do the dark period. I use only RO water and Hydro.
I use Hydrog uard up until I pull the roots out, never stop.