I am not sure this will help, but I have had success using plain old rattle-can Rustoleum Primer (white) for any tubes I paint. Make sure the can says it "bonds to plastic". While some use different colors for different color blanks, I have found that white enhances the color of any blank I have painted, but that is just my experience. I spray paint from both ends, shake it out, and then let it stand at least overnight. I think the secret is letting it alone while it really, really dries.
As for glue, I use white Gorilla Glue.
There are many virtues to leaving things alone to cure in almost every phase of pen turning and finishing. It has been a hard lesson for me to learn but I am now committed. (Until I get in a hurry....)