A sector on a Macintosh 400K/800K floppy contains 512 bytes of data and a few bytes of tags - either 12 or 20 bytes, I can't remember at the moment. 99.99% of Macintosh software ignores the tags. In fact, I've never seen any Mac program that uses the tag info. Tags are basically a hold-over from the Lisa. Yeah, 1.44 MB floppies don't store tags at all. Diskcopy 4.2 copies the tag info. Later versions of Diskcopy don't.
There's a disk copy program called Copy II Mac that *might* do something closer to bit-level copying, but I'm not sure. It may just duplicate what Diskcopy 4.2 does. Any program that does bit-level floppy access would have to bypass the Sony driver in the Mac's ROM, and control the IWM chip directly, which is not a small task.
Do you know for sure that the disks you need to copy are using a form of disk-level copy protection? Like non-standard sector headers or sector sizes? It not, then I don't think there's a need for anything other than Diskcopy 4.2. If you're concerned about read errors, then you could create multiple images from each floppy, and diff them to verify they're identical.
There's a disk copy program called Copy II Mac that *might* do something closer to bit-level copying, but I'm not sure. It may just duplicate what Diskcopy 4.2 does. Any program that does bit-level floppy access would have to bypass the Sony driver in the Mac's ROM, and control the IWM chip directly, which is not a small task.
Do you know for sure that the disks you need to copy are using a form of disk-level copy protection? Like non-standard sector headers or sector sizes? It not, then I don't think there's a need for anything other than Diskcopy 4.2. If you're concerned about read errors, then you could create multiple images from each floppy, and diff them to verify they're identical.