My MT-32 ("old" rev.01) arrived and I tested it out on it. It's pretty good.

Mine sounds pretty quiet compared to my SC-55...? So quiet in fact that I might need to add an amplifier just for the input to amplified speakers. Anybody else's?

Does anyone know any graphical/pseudographical editor/control programs for DOS or Windows that will let me set the reverb, for example?

You can edit reverb level from the front panel, but otherwise you need MIDI software to send SysEx. WSysEx should still work on Win 10.

And yes, it's a very quiet synth compared to future releases.