Don't worry about the time you flush not a big deal u less you been iseing neem or something that will make buds harsh. Most liquid salt based nutes along as you give you plants a good watering with no nutes last time b4 harvest you will be good. Everyone says shoot for a bunch if amber tricombs don't listen to that crap. You want 70 to 80% the hairs to change and turn inwards on the entire plant. After that happens look at tricombs you want about 90% of the tricombs ti be milky white and the rest to be about half clear half amber
When you wait till a bunch of amber tricombs buds don't get you high just give you a buzz. Also risk of buds starting to rot on the inside