Did it with DD again. It was pretty painless the second time, since I got it figured out. Swapped the drive on Monday afternoon, haven't had any freezes since to speak of.
Two things, for what it's worth: I ran in Windows (natively) all day Monday and didn't experience any freezes. I read reports of over-zealous Mac power saving settings doing this, but never any indication of how to disable said settings. Also checked for new firmware on the drive, there was none. Either way after cloning back to and installing the original drive, things are working just fine again.
Chalk this up to not-fully-developed technology.