Eric, on an award ticket, you may be permitted an extra stopover if the next available connecting flight in your seat class is not available within the 24-hour rule. This has happened to me several times, fortunately each time when I actually wanted to spend more time in the connecting city. So if you arrive in YYZ mid-afternoon and book a connecting flight late morning or early afternoon the following day, it should be legal, pending space available. You may receive a hassle from the res agent over the change, but I believe Aeroplan tickets generally follow normal rules in this regard.