Wondering if I use this with mods which add armor will I have to, or even can, add armors, or if it processes automatically.

It would be very good if you could add armor items in config - it would allow ModPack authors to really tune the experience. For example, for Iberia 2, I would ideally make full Gold Armor enchant only up to a certain level and need Terrasteel Botania Armor for enchantment level 30.

Good question, it currently looks at armor items, not armor level. So I'm guessing it wouldn't happen for new armor types added by other mods. It's something I can look into at some point though. Is there a mod in particular that would be a good test case?

Most recently I've done extensive playing with base metals and it's armors.
https://minecraft.curseforge.com/projects/base-metals