I think the changes I proposed shouldn't be considered final - there is probably a more correct way to fix it. However, I had a bad experience this evening which suggests something really should be done soon - either apply the temporary fix with intent to figure out a better solution, or fix it properly before the next release.
The 'bad experience' I had.... returning to my project and finding crunchy audio - leading to a new investigation to find the cause. Captured the audio in Audacity and noticed the familiar spikes were back.
Of course only at this point I realized I had been running the 'wrong' version of Hatari out of habit (the downloaded version via shortcut, instead of my local build which includes the patch, launched via CygwinX) and the audio problem went away when I remembered my error and launched the correct one :-) hehe.
D