The carbon assembly paste is good stuff. Most of them have tiny plastic bits that act as grit.

My LBS added a seatpost collar on my carbon seatpost when they sold me the bike. It was insurance against slipping down. It attaches to the post, above the clamp on the bike. I didn't have slipping problems, but it's helpful to see if the seatpost has moved at all, and I can put the post back exactly when I remove it.

Examples here