Well, that seemed to work!!!

So, I see now that the only thing I'm "missing" is that by using ST...it's not GM so songs that have sort of different instruments just will always be using whatever I've assigned in the ST channels...

Sax = soloist = trumpet = soloist = whatever I've picked in ST for ch8. i.e. it wont' change to match the intended instrument (sax, trumpet, flute, etc) as GM would.

But, that's the tradeoff if I like STs sounds more than typical MIDI instrument sounds, right?