"Tailor's guild" doesn't add an extra, second slot to Vaulter units: "Marine" and "Settler". Don't know about other Vaulter units as I never use them, but probably them as well. Said technology however, does add an extra accessory slot to Vaulter heroes.



Cheers.

They also do not seem to affect units from Drakken. (Heroes are fine just like what you experienced.)