Either solution could work, but we are trying to avoid delays. CANPAS is quite explicit regarding advance notice - unless it's an emergency they want at least two hours notice of arrival.
Calling Irving would be OK as a one-off but since we aren't landing there and using their services, it's a bit of a cheek just to expect them to help us all the time.
Surely it can't be uncommon when crossing Eastbound to file KBGR but have CYYT up your sleeve in case the winds are stronger than expected, or some other issue forces a divert?