must I start up from the drive I'm cloning?
 

I am probably paranoid, and hopefully I can get confirmation on this. Back when I was using Carbon Copy Cloner, I'm pretty sure I HAD to boot from the disk I was cloning, or else my "clone" would have incorrect permissions all over the place.

Ever since I switched to SuperDuper!, I've just continued in the habit of booting from the disk to be cloned. Is this necessary? Or can I make a perfect copy of a bootable drive that is NOT the active system disk? The user guide doesn't mention it either way, and I'd like someone to tell me for certain.

--flyleaf

It's not necessary, no, flyleaf. In fact, if anything, not booting from the drive will get you a more "accurate" copy.

more accurate? how so? (thinking about all the copies I might have screwed up now)

A drive you're running from is under constant change. As such, the copy is not fully "accurate" because the source could change after we've copied something. That doesn't mean it's a "bad" copy, as the files are indeed captured at the point of copying. Just that the copies might diverge soon after.