After a little hiatus, I'm back on this project. First up, repairing the open SW antenna coil.
A helpful ARF member sent me a nice diagram showing how the coils are wound.
The main coil is the tapped secondary. The coil floating inside is the BC primary and the open coil on the outside bottom is the SW primary.
I carefully unwound it and found two breaks.
I cleaned off the debris with rubbing alcohol and gave it a coat of shellac.
I've had this big spool of wire for years. The gauge is unmarked but it looks identical to the old wire. That's good enough for me.