*UPDATED*
So, I find that I
can load the FS-UAE Arcade app correctly, but
only when I run the binary file from within the App Bundle - '/Applications/FS-UAE Arcade.app/Contents/MacOS/fs-uae-arcade'.
However, the Mac Terminal window opens when ever I do this so it's not ideal.
**UPDATED**
The only working version I can find is FS-Arcade 2.9.7