I too used the Glowshift adapter. Opening the package I realized they give you the wrong o-ring. I replaced it with a larger one and never leaked. The oring seals the connection. NO sealants of any kind are necessary. If you did, then it's wrong.

 

I used the GlowShift adapter as well. No issues that I have seen and like the others no sealant. Just installed it until it was flush/tight.

 

The problem with using any sealants other than the O-ring is that they can get into the fuel system and cause problems.