Jackson, you are a worrier, chill out brother, this is meant to be fun.
The plants look absolutely terrific ! I mean that whole heartedly..........teriffic !
Now then as for amber or brown trichs, you don't need a loupe, Bog standard eyesight will tell you if they are browning up. If you can't see it, they are not ready. Period.
Most Autos will go at least 80/90 days........however, your leaves look at the end side of their cycle, so I would question your dates. Leave them be for at least another week. Forget all that flushing crap etc, just run them as far as you can.
And relax my friend and enjoy your grow..........eP.