Awesome! That's kind of the way I've been leaning after doing the research today. The biggest question I'll have to discuss with the owner is how many clones he's interested in using. Obviously, the hope is to never use it. But, I've been down that path before with drives, and sure wish I'd had a clone to throw in the machine.
I looked over CCC and SD. But, CCC looks so much more polished, and there's no small amount of popular posts for either one.
Did you ever look at offsite backup? I looked as several as a third layer of defense. But, one of the sites kind of scared me when they said the original backup will take around two weeks to complete! Not sure what size that backup is though, so perhaps that's for several Tb.
Later,
Robert