I notice that it takes a couple of weeks for the tips to brown and lupulin to darken. I also live in IL with high humidity and rain in late summer. I'll look for a few top cones that are almost all brown, and consider it time to harvest and toss the browned ones. I use the papery feel test, squish test, and sniff test. It takes me about 3 days to dry my hops in the oast with a fan on low.
This year I am considering the time that I harvest, and thinking about chopping my sprouts to the ground accordingly in spring. Last week I harvested my Cascade and Chinook. This week or next I'll be harvesting my Zeus and Nugget. Next year, I'm thinking of chopping my Cascade and Chinook sprouts to the ground 2 weeks after I chop my Nugget and Zeus sprouts to coordinate harvests. Theoretically, they'll mature at about the same time next year. Does this make sense, given the plants will be given the same growing Conditions, soil, and water? Should I just hack it all at the same time and have staggered harvests?