ozbusdriver to answer your question re how often we have 6 in the cct , mon-fri on good wx days it has been not unusual to have 8-10 in Eastern cct, this reflects the international students whereas weekends are mainly local pilots so not nearly as busy.
Remember MB used to only allow around 5-6 in each cct in the 80s and 90s and both ccts were quite busy until the recession hit in early 90s and MB became ghostly quiet.
After almost 2 weeks of operation I have witnessed and been involved in 4 less than desirable t'off/landing clearances which should not have occured and i put down to controller workload associated with the new procedure.
Having all runways requiring clearance to cross adds zero to efficiency , has a measurable negative safety outcome as mentioned above and requires an additional controller to operate SMC.
Thanks for the consultation CASA....