I've made exactly one mod so far in the Creation Kit, a personal standalone follower from a previous save. The character used data from Enhanced Character Edit, and in order to import that face data it needed to be saved to slot 24 in ECE so the Creation Kit could read it as NoseType32. This much I know.

However I would like to make a new custom follower from a new save game and I don't know if there are other slots I can save to in Enhanced Character Edit that the Creation Kit can read. So if I use the same method as I did before, would overwriting the data in Slot 24 change my first custom follower? Or would they stay the same because they've already been packed up and saved as their own .esp?