My 789 YYZ-YVR today had 20+ on the upgrade list. 6 of them were from PY. There were 4 seats available.

Also if the 1900 flight is AC 33, the "direct flight" imposes other eUpgrade challenges.

I'd actually be more inclined to take the 2000 if it's a 789, mostly because we can actually tell you how the upgrades work on it, rather than having to rely on a few anecdotes and a lot of speculation.