Lax in getting an update for anyone who cares... hopefully no one gets sick of reading about the little details. I received the replacement compound gear, and it was in very good condition. It bolted right up. I found the parts list for the lathe here on the site also. It has a print of the gear arrangements for turning and trhreading, like the one inside of the gear cover. Only difference is I can enlarge it on my tablet and actually read the order of the gears.
I assembled a set of gears for turning, I think that I chose 0.0035 inch/revolution, the 2nd finest rate. Kind of fiddly getting the wrenches on the stud that positions the banjo. I'm going to make a few updates on the nuts to ease getting a wrench on them. And waiting for a milling attachment. Not the best solution, but I'm not a machinist, just a hacker who needs to make the occasional slot or flat surface.
And the garage is currently a mess still, with stuff slowly but surely getting into place. I put new wheels and tires on the rolling workbench I made 20 odd years ago, but they are slightly larger diameter than the original ones. So now I have to make clearance. Or grind the diameter down a little bit! Just like grinding race tires...