Thanks for the suggestions.

As this is a stereo project, the camera ID will be used to ID which camera (1, 2, L, R).

I understand "soon" we might have alpha-numeric, "permanent" card IDs, which will be great.

Once we hit the 999 ceiling, we'll copy to a different folder and then apply a global rename adding a "b" suffix or whatever. An extra step, but renaming (utility) is easier than sweating other options.