I just did't like the tiny 1/4x28 thread of the smaller drum from the start.
So the 1/2 drum with the larger thread would be my choice.
If I did shim it,,I'd put a steel sleeve around the small dia drum to bring it up to proper diameter. Then it's steel on steel when the hammer batters it against the plate.
If you don't have a lathe,,then the 1/2 moon shim is much easier.
..or just install the new 1/2d drum.
Lots of ways to go,,just depends on how much time you want to spend and what your expectations of service might be.
JMHO