To configure administration for local groups
To do a mix of both, select the first option for SonicWall Read-Only Admins, and then create another group that is a member of this group, but that has the second option selected (but not vice versa).
If a user is a member of a read-only admin group and has membership in no other administrative groups, then that member gets full-level access (as per SonicWall Administrators) restricted to read-only.