no , you should look at the buds while they are still on the plant (if possible). a leaf is fine too , you just have to get close to the bud where all the tricks are pouring out. you want to take a good look at two or three places of the plant an if you see 1 or 2 purple tricks in each area then its done.....or has been done for a couple days.
a good place to get a feel for the purple is probably gonna be in that bleached bud. i would imagine the extra light burnt up a bunch of the crystal heads on that bud, so i bet if you look there , there will be a bunch of amber/purple/dead tricks. that part of the plant dont count though, that wasnt supposed to happen.
that piece you was pointing at is a prime candidate to smoke. it really wont make that big of difference where you take it from , long as it aint no whole branch or nothin. an as long as you only do it once.
your gonna lose 75% in water , so i would take a couple pieces or a piece a lil bigger then that , so you at least have a joint. depending on how much you wanna take , i would probably go ahead an steal that bleached bud, just because it has damage on it already.
the best way to smoke it fast is to at least let it dry all the way on its own, then smoke. (if you aint gonna wait for a cure.... i wouldnt)
basically if it drys in one day , it will taste very green an not very strong...... if it takes 4 or 5 days to dry then it will taste alot better an be more potent. (thats where a good cure comes in)
forget flushing , i would give her one more dose of pk an no n , then pick her after thats used up. (a week or so) there is nothing in that dirt to "flush out". if you think you got a bunch of buildup in the pot then a flush might help a lil , but with as healthy as your plant is , she is eating everything you put in there. there is no buildup. just give her water a couple times after the last dose of food just to make sure , but do not flood it out in an attempt to "flush".
in a good dirt like you have the food molacules are bonded to the dirt/bacteria/fungus ect... you cant break that bond with water or anything else.
soil