TOPIC: Permissions for "Registration Manager"

I'm trying to setup users who should only have the permission to manage any registration (add, delete, modify), but not do anything else in DT Register or in Joomla.

I succeeded partially by creating a group "FF-Registration" as a child of the standard group "Registered > Author". In DT Register I only allow this group "Manage Records" and "CSV Export"

Accounts in this group do have fairly limited access, but they can still edit all event details, even though all events are owned by the Super User.

Regarding another aspect: Is there any way to find out who last changed a registration record? We have multiple people who can manage all records, and it would be useful to know who did certain changes.