After hearing about it for years I finally bought a copy of Hard Disk Toolkit. It's version 2.0 and the manual is a hulking beast of a book. I've used just about every other hard disk utility known to mankind on vintage Macs except this one. Hopefully it will be as good as advertised (the reviews from the 1990s were excellent).

I think I'll use it on a 100MB Quantum ProDrive LPS (non-Apple). There seem to be a ton of bells and whistles on it and I can't wait to finally try out the feature set!