The one who flew, that's very nice of you to post all this info
Thanks a lot for the links!
I haven't tried playing Dune 2 through DOSBox with TiMidity (although other DOS games with MIDI music worked fine with the TiMidity++/Twsynth combo that installs the alternate MIDI driver on Windows), I've been using pure GUS emulation in DOSBox along with
this patch that adds GUS compatibility to Dune 2.