Re: Rag Joint Issue
I've never tried to get a rim trued with a sprocket installed so I can't answer you on that. I suppose you'd have nothing to loose by trying. Take the wheel in and ask. All they could do is say yes or no. If they'll do it I'd surely want to re-check your sprocket after they do the rim to make sure nothing changed. Let us know.
There are also lots of good tutorials on-line that would show you how to do it yourself. I've done a couple and it isn't the black art that the bike shops would have you believe.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"