I've never glued one in yet but I will tell you I have a sinking feeling in my stomach every time no matter how much release agent I use.
I've used both the action screw and dedicated bedding screw/surgical tubing method and so far don't have a strong preference.
Can you warm up Marine Tex to get it to flow easier?
Can't speak for Marine Tex but I have done this with Devcon with success.
