Thanks. These are most of the staples I mentioned, but also a few I haven't heard of.
Parkdale is new to me and has some merit. It can graph R/W but it's clunky and I found it inconsistent.
Ultimately I managed to get HD Tune to work. I think the key was to first delete the partition/filesystem.
It still crashed once without saying anything, but a later attempt worked okay. Not sure what I did different.