SC-55 (and many other General MIDI devices of the era) generates it's basic sound palette by accessing a bank of preset sounds, similar to how Soundfonts function. That is why Soundfont-based systems can be used for emulation.
MT-32 (which is not a General MIDI device) generates it's sound palette PARTLY by the above method, but ALSO by certain unique methods involving custom sounds and real-time calculations. Therefore, soundfonts cannot by themselves suffice to emulate an MT-32. The application "Munt" was written specifically to fill that MT-32 niche, with the necessary real-time capabilities in addition to the stored bank sounds.
Supporter of PicoGUS, PicoMEM, mt32-pi, WavetablePi, Throttle Blaster, Voltage Blaster, GBS-Control, GP2040-CE, RetroNAS.