I know of another technique that requires special hardware for Apple II, it's a floppy read mechanism that can read / re-read the floppy at the 'flux' level and

I know of another technique that requires special hardware for Apple II, it's a floppy read mechanism that can read / re-read the floppy at the 'flux' level and build up a statistical profile which often is correct about the hard to read areas. ref (https://appletimewarp.libsyn.com/episode-6-applesauce-with-john-keoni-morris https://appletimewarp.libsyn.com/episode-6-applesauce-with-j...)