Well, I got my 2nd Genes, and used the Backup/REstore operation (with "Audio Files" ticked also), and it worked GREAT! I couldn't believe how fast all my custom stuff was transferred (saved then restored). It seemed to have saved everything - my Registrations, custom Voice (but not expansion voices), my custom Effects, my MIDI settings, my pedal polarity settings, my audio files, MP3s and MIDI files etc. etc.
I did have to separately get my Expansion voices in - this was easy too - I just:
1) made an "Instrument File" on the new Genus (under the "Expansion" sub-menu)
2) Imported this "instrument file" into YEM on my Mac
3) Made a new Pack file using YEM, after selecting the newly-imported Instrument File
4) Loaded that new Pack file into the new Genus (under "Expansion" sub-menu)
So with very little effort, my new Genos seems to be 100% identical to my other one - it will take time to try many more things to be sure, but it seemed to work VERY well! What I thought was going to be a weekend project, ending being a ~90 minute project, including time it takes to create the Pack file and time to load it.
Jim