I use the po'boy throw levers on some scopes.
Buy the universal coaster here, you get 2 in the package.
Coasters | Breakaway Tackle & Development
They are not pretty, but they work.
For metal zoom rings, I cut a little strip of innertube (rubber band will do, too) between the coaster and the zoom ring; this also eliminates the possibility of bitching up the finish on the scope.
edit; here's a picture I found on the interweb of a po'boy throw lever installed
Thanks my friend. I got the thing on there this afternoon. Tapped it with 8-32 and Loc-tited a set screw in there which snugged it up pretty good. The rubber band inner tube idea is a good one but there is no way it would fit between the scope and throw lever. I put a little grease on the lugs of the thing in case there is any movement put it seems like a good fit. Not sure why they use that little fucking screw though. IDK.