Does anyone ever do this ie unscrew the collar on the Reverb and pack the collar with grease (such as slick honey)? Anything to be gained ie something to do in between services to preserve seal life etc?

Not often but yes on a new reverb to make sure there is some slick honey in there and once in a blue moon to make sure muck isn’t getting past the seal.

Yes it can help a bit, but not as much as a good bleed.

Yes – I do this (pack with grease) when I can’t find the time to strip them further.

I think it helps ?