If you use a jig without a base, and you have an anvil, that should work fine(ofc you will not break the anvil)
This was my case, and luckily I was able to use it without too much hassle securing the washer with some tape on the base.
A CNC-cut aluminum base is cool anyway: can you share a few pictures?
I do agree: that it's overkill, but it might be fun to use it!