This remark from a former RAF Canberra pilot who was sent to Canada for his flying training. Of course not all Harvards were in the circuit at the same time but you can bet circuit discipline was tight.
"I remember training in Canada on the Harvard at RCAF Penhold Alberta (near Red Deer) in 1957.It was quite normal to have 60 or 70 Harvards serviceable on the line in the morning.(100 deg F in Summer -40 in winter) Cheers"