The ring is upright, perpendicular to the build table, and the inside is round (I checked against a mandrel). I will re-calibrate the build table and the project just to make sure and then run a calibration print and post it here.
I'll make a note of that once my warranty period is up. I do notice the screw wobbling a bit at the very top but I don't know how much of an issue that effectively is. Is it worth getting a new Z screw rod?
Backtracking to the original topic, my original x motor somehow is working again (nothing was done to it) so I have reinstalled it and ran a 6.5hr print with no jamming errors. What the heck? I'm baffled.
I am, however, still getting the wobbles.
If you look in the shadowed part of the shank on the right, you can see the wobbles.