Just got around to replacing the window seals on the Puck, and noticed these new seals have an adhesive sticky liner. Should I use additional butyl rubber sealant with these "Teroson Butyl 2759" is not really available - what would you recommend? Ta in advance.

When I did my fixed Puck window I didn't use any extra sealant, have a look at this window rubber replacement thread

https://files.homepagemodules.de/b614104/f14t621p4908n2.pdf

Replacing window rubbers step by step guides