Consider using alias/symbolic links for unchanged files.

[typesupply]

Duplicating unchanged files* seems like it could result in unnecessary storage. For example, if a 250 mb PDF is unchanged from the first through 256th state, it doesn't need to be copied 256 times. Consider optionally using alias/symbolic links to the previous state in these situations. Maybe something like this:

Duplicate Unchanged Files:
( ) Always
( ) Only when files are less than 1 mb.

*This does not apply to unchanged files within a UFO. Don't put symbolic links inside of a UFO.

[typesupply]

Here's how to manage aliases with PyObjC: https://stackoverflow.com/questions/48862093/how-to-read-change-and-write-macos-file-alias-from-python