Cronk, I only use the seed banks, to get an idea of how long, they are supposed to take, but that's it, I've seem them be off many times, might be because, they know how, and I dont.
But when I used to flush, and still do ever now and then, I go by the trichs on the buds, not the leaves, And when is see a few amber for the first time, that's when I start the flush.
MJ, can live longer than you think, just feeding off of herself. And I like to see mine turn yellow the last 2-3weeks, that's the way they grow, naturally out in the woods.
Ps- you need to try a plant without flushing, one time, just to see if you can tell a difference.
Anyway good luck, you know what, you are doing.