Bob,
Viola! It's working.
Your last comment did the trick, specifically, naming the MC Tivo Server in the options dialog. All this time I never filled in the name field.
So here's what I got now.
Tivo Desktop 2.8.3 is running using Bonjour and not Beacon. that's what they recommend.
MC19 is running with Tivo Server at port 8070. It wouldn't start up at 8080. I think Tivo Desktop is using that somehow, maybe when it was in Beacon, not sure.
MC19 TiVo Server name was set to MCTivo.
So now on the Tivo I see both the Tivo Desktop shared music folder and the MC19 music library. The attached image shows what I see in Tivo with Standard Definition menus. The 2 entries named MCTivo are from the MC Tivo Server based on the name I put in the options dialog.
Thanks for sticking with me on this Bob. Maybe the Wiki also needs to say to give the Tivo Server a name.
-phil