Couple of things that have not been mentioned.

I seem to think that Toronto flights go from the B Gates, so you'll need to factor in some time to get across on the shuttle. Doesn't take long, but if you don't want to be in a rush, you may want to leave in good time. There is a lounge at the B gates - it's not the Concorde Room, but it is pleasant enough for 20 to 30 minutes.

Also, YYZ has a separate First Lounge that has been renovated to current Galleries style. You can have waiter served dinner on your return. My last experience of YYZ lounge catering was the food was OK but the wines distinctly lacking.