I can't believe I missed that other switch!
Thanks for the '54 schematics.
After some testing, I have the wires correctly connected.
Yet now I still get just a single click when I try the starter, so I'll check the continuity of the N/S switch and then pull the starter itself to check it if the switch is OK. I'll need to pick up a 5/8" obstruction wrench from Sears on the way in tomorrow in case I need to remove the starter. I've never needed one of those until now.