@John, now that you've seen so of this, I was wondering if your Super Chuffer and Chuff Generator could be used with DCC at all when used in a steam engine? Mainly the Chuff Generator used as the input to the decoder to trigger the sound instead of using a reed switch or hall sensor. But if I could use the Super Chuffer too, that would be awesome.
You can sync the steam chuffs to the wheel rotation quite accurately with just a couple CVs in the Loksound, so that you always have four chuffs per rev (or however many you like). No hardware needed.
If you want to have the chuffs occur at a specific wheel orientation, then yeah, I think you need hardware for that.