Lollipop or no? When to stop?

It's hard to know which grow you are talking about. After you're confident the flower stretch is over, its your choice to remove any bits that don't receive much light lower down. I can say from personal exp. You definitely want to do anything below 4/5 nodes on each stem. 🌱👍

Maybe don't do it all, just use the popcorn nugs for hash at the end. Prune them if you want, but not cutting and stressing your plant is just as likely, if not more likely to make a positive difference to your upper canopy. Some do, some don't. They end up with great results either way. Here is a link to see what the professionals say: https://www.cocoforcannabis.com/community/photons_corner/to-defoliate-or-not-to-defoliate/