"When arranging the song I would use the C7th designation in the base "APC" track"

Thanks Larry.

So, if you allow the APC bass notes to sound, you would hear the proper bass notes for the C7 chords without the -9th. It makes sense musically but doesn't seem to sound right to me when I play it. I can see how I might do it in a sequence by inserting the -9th in the right hand, but I think it is beyond my abilities to do it on the fly. And, I don't know how to do it at all if I am trying to use Technichord.

I think this is all beyond my limited knowledge . . .