The latest "official" ScummVM for 68K (above) now also has an option to adjust the audio playback frequency. Dropping it to half of normal really improves playback quality and eliminates chopiness.
But the "newer" games on ScummVM like Monkey3 and the Broken Swords just seem to be too much for the poor little 68K to handle (since they're double the resolution of older games). Even my A1 struggles with them.
