I have a few questions about flushing plants.

I started my mix with 4 bags of sunshine mix, added blood, bone meal, lime, marine cuisine plant food, by fox farm, worm castings, and coco coir.

I mixed the soil way too hot.

I tested runoff, and the pen was flashing. I added lots and lots of coir, to cool things down a bit.

I flush a plant if I have one that looks to have nute burn, or wilting.
I have been told not to feed a plant that has been flushed, and I have been told to feed in the last volume of water flush.

Which is the right way to go?

Also I am growing plants from breeder mixes, and dont know exact flower times,
I want to give the plants a good 2 week flush before harvest, but I'm not sure when to start flushing.
I want amber crystals for couch locking stone, and want to pull the top half of the plant to let the bottom get more light to finish up good and ripe.

can a plant get too ripe?

It's a common noob move to cut the buds to early, but Soma, says to let the plants go for 2 more weeks, AFTER you think it's time to harvest.

I think it's time to harvest when half the glands are amber. Correct? But how do you know when this will happen in 2 weeks, so I can start flushing?