I had a GW-8 for a while. Although, technically, it is style compatible with the G70, there's a LOT of work involved in getting them to sound right. The lack of ANY onboard style editing tools other than mere volume and pan controls for style parts makes adjusting the part sounds and kits (they are not 100% compatible) a trial and erro process in the G70.... transfer style to GW-8, listen to what you want changed, go back to G70, make adjustments, transfer to GW-8, listen to adjustments (finally), go back to G70, make more adjustments, transfer to GW-8, listen again, and so on...

Sorry, but my idea of a backup is something you load the EXACT same data in as is in your main axe, and go out and gig. Not spend months so it can do that...