[dnanian]

Thanks for the compliments!

The Sandbox has a size based on the number of applications you've got installed, especially those that have data stored in /Library. So, the various Pro Tools, or Garage Band, tend to create larger ones... without, smaller.

Regardless, you want to make sure it's large enough to store updates, VM swap files and temporary files, so don't size too small.

Since a Safety Clone is not a backup -- it's a system checkpoint -- it doesn't really matter what drive it's on, except for convenience's sake. I'd recommend storing your backup on an external drive that gets less use, for obvious reasons. And, if you're worried about your internal drive, make sure you get SMART Reporter (check VT) and consider replacing it with a server-rated 24-hour duty cycle drive like the MaxLine III.

Hope that helps.