What time of day will you be traveling through Pearson? That will make a big difference as 7 am on a Monday morning will be much busier than later in the day. Regardless of your airline you will have to claim your bags prior to clearing customs, followed by dropping your bags back on the belt and passing through the security check point again after customs so the faster you can get to the belt and grab your bags the better off you will be.
If your flight is running late and time is getting short, feel free to check with one of the attendants looking after the customs line-up as they may be willing to put you ahead of others if they feel you will miss your flight by standing in the regular line (and be sure to tell them you are a connecting passenger so they are aware that you didn't just show up late to the airport and expect special treatment). The line in Toronto can be quite daunting, much more so than Halifax, Montreal etc. in my experience so don't be afraid to ask if you think you may be too short on time.