If HD SC setup fails, try a patched version of Drive Setup. HD SC setup will fail a drive if you breathe on it too hard whereas Drive Setup tends to be a bit more ignorant regarding surface defects. Really handy with the Powerbooks where the small hard drives are about impossible to find.

Also, popping my own CMS drive open I now remember that only the first three dip switches sets the drive ID and the last one I think turned termination on and off. The rest aren't connected to anything.