What do you think of my idea of trying a dynamic deletion of Rita's two extraneous internal partitions while she's booted into Sierra on her internal?
If it's successful, everyone saves a whole lot of time and effort and she can move right on to upgrading to Catalina, and if not, she remains at square one, i.e. still having to erase her internal.
Sierra on her external must, of course, be totally current, i.e. a mirror of her internal, but that's inherent in anything she does.
