hello John,
I used Pro-24 back in the days, it was quite cool: http://www.atarimania.com/utility-atari
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But later I used Cubase (or Cubase lite, I don't remember well). Both are from Steinberg, I think Cubase is more advanced. Probably you need a dongle to use Cubase because I'm not sure there is a reliable crack for it (that's why I think it was Cubase Lite I had because I had no dongle).
I used Midi program changes in Cubase, so my expander (Roland D-110) could automatically switch to the correct instruments when the song started to play (it's just a midi event to insert in the track).
I can understand people use old chips to make music with them, but for MIDI, it will just sound the same, so why not using a more modern tool? Well, I must admit I had already thought to use my Atari ST for this purpose as well. But I already have one. For a decent Atari ST(e), it will cost you around 50-70 €. Try to get an STE because if you want to compose Chiptune with Maxymiser in the future, you get DMA channels and it also has CINCH / RCA outputs.
Anyway, in Logic Pro you should be able to program midi program changes as well: http://www.plugorama.com/kb.php?id=33