[RodB]

As the power cord was originally wired, the wires were probably connected directly to the bakelite block then one side went to the power switch and the other to the power transformer primary. The other primary lead went to the other side of the power switch.

To do the rewire, you connect power transformer primary across the bakelite block caps, the hot side of the cord to the power switch, then the neutral side of the cord to one transformer primary lead and finally the other transformer primary lead to the unused power switch terminal. If you don't have a polarized plug on the cord then it won't matter which cord wire you start with.

   

The toggle switch shorts the 0.03 capacitor and changes the tone. You're right about the black beauty replacing the bb capacitor (66) so it's time to discard it. Or you can sell it on eBay for $15. Yes, the cut wire on the bb terminal goes to the tap terminal on the volume control. It will be the terminal by itself away from the other three. You will notice that terminal on the bakelite block is not connected to any component inside the block.