I glassed/floated my M77 back in the 80s and it sure made a difference. IIRC, the Brownells kits were good for about two jobs back then.
In addition to the release agent, it's a good idea to coat screw threads with paste wax or grease.
Sorry if this was in the thread, I haven't read all of it, but you should also clean out the thread impressions in the glass with a round file or something. Keeps things from twisting when the guard screws are tightened.
