Well, I can't see them because the pix are too big.
I wouldn't start flushing until your buds are ripe, at least 2 more weeks. And with ebb&flow, usually the medium is loose and airy, and is easily flushed of nutrient build-up. In that case I flush for 5 days.
Harvest has nothing to do with a cola turning . You harvest by Trich.
50% cloudy 50% amber I would flush with PHed water.
I wait also. But I would flush longer until that plant is dead most likely your using chemical ferts. That stuffs going to taste nasty . Ide flush if this were the case for 2 3 weeks. You'll lose on yield gain inpotency AND TASTE.