> you need to skip this step, it's for AOS only. [...] I personally
> had no timing problems with modules i played.

I followed the steps (except #7) and DeliTracker works fine now on MorphOS 3.1 on my Mac mini G4. Thanks :-) I remember that I had read fingus' instructions back then when he posted them to amigaworld.net but silly me didn't even think to attempt to follow them due to mention of step #7.
As I see there has already been a discussion on the timing issue (that is not there under MorphOS):

https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=2094&forum=9&start=12

And there's an ARexx script that's supposed to help with running on MorphOS:
http://wickedvinz.free.fr/files/Delitracker2_MOS.lha