[Eliot Ness]

That's pretty interesting with all of the old modifications.  One radio I needed to return to stock in the past I printed off the schematic and used colored pencils to trace the wiring and components as I brought them back to normal.  In your case you might want to enlarge the schematic and just print off sections so it's easier to trace and follow.

I've only had one movie dial set and it did not have electric  tuning, but all of my other sets with electric tuning were able to be tuned manually, so I'd check for something binding...... hopefully there isn't warped pot metal causing it.