Hi Paul,
I don't know anything specific about your globe - cool find, by the way - but I did have an idea here.
It looks to me like the bottom of the spindle is held by basically a simple crimp of the metal the shaft slides through. It doesn't look like there's a way to release the crimp with the shaft in place, but if there was that would be the place to start. Otherwise, my first impression would be to use a slim punch to drive the shaft out of the crimp, assuming the top of the globe is held on by that same sort of crimp.
I'm not sure what is causing the globe to not spin freely, but I wouldn't think it would be too hard to find another nylon spacer to insert at the bottom to raise it up the amount you've indicated. Since it looks like it's already got a nylon washer on it, the addition of a second one should give you a pretty friction-free rotation.
Those are my own thoughts on the subject; I'd be curious to hear from anyone who has actual experience with these things as well. Good luck with it; let us know how it goes!