I took mine (95 model) apart, worked my way around the seam in the plastic case, started with a razor blade, then up to a thin piece of alum i had laying around. got it apart, just like you would do to replace the glass. After i tighened up the bolt, i put just a little touch of cement on the plastic case and reassembled.
Been several years ago, still no droop.
I'm not saying this is the best way, but it worked for me. It didnt occur to me at the time to slit the rubber.
Patience required but now you cant see any evidence that it was ever taken apart.
Good luck to ye.