John,

The other possible challenge with the O2 mount is that the older steel bottles have a longer neck that the aluminum ones. I ran into that problem in my Libelle and needed to make an extension to the tank to get the neck clamp to work.

Mountain High now offers an extension like the one I made.

https://www.mhoxygen.com/product/cyl...r-port-3-4-16/

Mike B.