Thanks for that info Dan!

I'm still not clear on the channel assignments as I had tried changing channels in Kontakt and also tried changing channels in the Reaper MIDI editor and none of it worked. But, as these things often go, once I got deep into areas I know little about I'm sure I was doing something wrong and couldn't get it to work.

But once I set Kontakt to omni...OMG! The heavens opened up and my BIAB-generated piano MIDI from a RealTrack sounded amazing! I spent the rest of the evening auditioning tons of Kontakt instruments on that one track! It was a delightful breakthrough for me as I knew (hoped) this was possible but had never gotten it to work in the occasional brief attempt.

At the end of the evening I briefly went back to trying to get drums exported as MIDI from notated BIAB RealTracks to work using the various drum kits I have in Kontakt. But I was unable to get it working properly. They made sounds but didn't sound right compared to how they sounded in BIAB. Maybe time of night? Maybe that transpose thing you mentioned?

Tonight I will try the transpose technique you suggested. Would I do this in the Reaper MIDI editor?

Thanks again for your help! This is opening up amazing pathways I suspected were there but had not yet been able to traverse!