The constraint is the airline baggage cut-off time. As you have to check-in bags an hour prior, that "hour" (more like 40 minutes) after dropping bags off is when you go thru security and CBP.

Bare minimum will be two hours = 60 minutes to get to Canada landside and 60 minutes prior to check bags. Risk of course is if it takes more than 1 hour to get to landside with you bags.

If bags are check-thru (or no bags), then the International -> US Preclearance bypass would be available.