[dnanian]

Yes, you can do a Smart Update with "Backup - all files" from Sandbox to Mac HD... but doing this in an automated fashion isn't wise due to the fact that you only want to update Macintosh HD when you're sure the Sandbox is OK.

But, then, yes -- you back up "Macintosh HD" with "Backup - all files" and Smart Update to your real backup. Do not back up the Sandbox!