Without checking, I'd say it's 45 mins. The published limit might be only 30 mins for a domestic bag check-in, but do you really want to risk your bag not making it onto the Narita flight?

I am also YOW-based and connect very regularly through YYZ or YUL to intl flights. The thing I pay very close attention to is the connection time, especially for YYZ. You look like you will have 1hr 20 which should be fine. I try to depart YOW one extra flight earlier than I need to avoid arriving a day late at my international destination.
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13F