Hub drilling

There are machines that do this and they are accurate.

One of my friends has one.

The first thing I'd do is make sure you can get a drum that fits the shoes and backing plate.

I have to correct the statement about A body drums.
They did NOT stay SBP.
73 and up disk brake cars had LBP rear drums.

If drums are available, I'd consider plugging the SBP holes and welding them in.