Time to harv

You need a jeweler's magnifying lens or scope to look at the trichomes. They cost about $20 but give you the most accurate picture. From the pics, the number of weeks in flower so far, and that you're growing a high yield strain, I'd estimate 3 weeks. My first grow it always seemed like I would be close to finishing when I hit the point you are, even though in reality I was a long way off (that one went just over 90 days). Even without the scope, you'll see majpr changes when you really are close: most hairs will have darkened and curled inward, revealing bud underneath; the smell will sharply increase; and if its normal for the strain and if you're reducing humidity as you should be (to about 40-45% by now, aiming for 30% the final week if you can hit it), you'll see more and more "frostiness" as the plant produces visible levels of THC through the trichomes (it looks like glitter).