I would like to update the access for some base collaborators who currently have full access to base & Interface to Interface-only access (these users were already shared as collaborators before it was possible to share an Interface without giving access to the base).
In this case, does anyone know if I have to entirely delete these users from the base and then re-share them as Interface-only contributors (with the 'Allow access to data in the base' unchecked upon share)?
Depends on level of access. I believe if a user is shared with access level of commenter or above then yes, there is a cost. However a user shared on an interface with read only access does not have an associated cost