The vast majority of pistils will have changed color and retracted near harvest. The seed bracts will all swell up thick and there will be an overall change in color, sort of a rusty tinge to the bud. You'll also notice your buds all start to sag much more near the end. Under a scope, there will be plenty of amber when the buds are ripe-don't look for 5% or 20% or whatever, just combine what you see in the scope, with the other signs of ripeness. You'll have plenty of time in the harvest window, it's almost impossible to chop too late. Keep an eye on the trichomes throughout the grow, and watch how they stand up and swell up just like the bud itself does. Don't be scared lots of amber trichomes. Also, keep smelling your buds regularly, and you'll notice a final burst of terpenes in the last week or two and the bud will smell much more potent. You want to wait for all these signs so that your buds won't get that grassy smell when they dry, and it will also mean the difference between nice dense buds when dry and little airy puffballs.
