Looking to fly from YVR to LIM in the spring on flights AC34 and AC80. There would be an overnight layover of 21h20m in YYZ. It's not long enough to count as a stopover, since it's connecting to an international flight, but I would be leaving the airport; will one SSWU still work to upgrade both flights?

In case it matters, aircanada.com doesn't want to offer AC34 as an option unless I book it as multi-city (YVR-YYZ,YYZ-LIM), but using multi-city, it still falls under the same fare rules (which say "no stopovers permitted").