Those plants are weeks away from being done. Anyway...to each his own!
I always hang the whole plant. I've learned to ignore that "when the stems snap" advice. That's way too dry, in my experience.
From now on, I'm going to start jarring things up long before the stems snap, trimming when the buds are still fairly moist and then being careful about burping the jars more -and even taking all the buds out of the jar for a few minutes and rearranging their orientation in the jar on a regular basis to avoid mold. It's going to take longer and be more of a hassle to do, but here's why:
This last run, I let the 10-12 week plants go 15 weeks (wanted to see what the results would be -looking for lots of milk and amber). The plants basically died before chop and lost a lot of smell. I hung them to dry but they were already dry. I should have just gone straight to trimming and jarring. The extra hang time, caused the buds to dry out too much and when they finally hit the jars, there just wasn't enough moisture in them to cure properly. I usually see 70-80% humidity when I first start jarring up the buds and then slowly taking them down to ~60-65% after that. But this last run, the buds hit the jars and it took a couple days before the humidity even came up to 55%. Like I say, they just didn't cure. I added a Boveda after the fact, but it was just too late. All that work and time only to end up with mild-flavored, mediocre-effect buds. They DO look good, though!
It was an experiment. I learned. I'll probably just press the rest of the buds into flower rosin on my press.
Good luck!