FYI, there's a clarinet player in Boston on this forum who posted a month or so ago to say that he has developed and is beta testing a new source-destination editing solution for Reaper; it's in the Source/Destination editing thread in the Feature Request section of this forum. I sent him a PM but haven't heard back...I'm curious to see what he has come up with. See
https://forum.cockos.com/showthread.php?t=170775