restriction on folders

If i want to create a new folder with permissions so only 4 users have edit perms but all other users have read only perms, would it be easier to create a new group with edit perms and apply this to the 4 users and then create another group and apply the read only role to them, or add the read only permission to every existing role and create a new role and apply the edit role to the 4 users.

Thanks

SolidworksAdministration