That sounds like my Mk-3 snuffer. We secured the bag by tightening the bag around a moulded flange. No problems with the bag..
I think you might get more friction by running the bag over the snuffers mouth. Friction is bad, something to consider.
Not necessary, depends highly on fabric vs ring material friction differences assuming that mouth of the bag doesn't collapse. I believe that I got good fabric with very little friction.
Anyways some snuffer ring pics that were promised:
The small table leg is a mould for spi pole same diameter than pole <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" />. Snuffer bag isn't done yet so I haven't put anything about this on my blog yet.