However, given that Canada doesn’t have the same consumer protection when it comes to automotive warranty, I would stick with 0w20 until the warranty period is over.
I had thought of this as well but have 25 litres of Pennzoil syn 5w30 and 20 litres of 0w20 sitting in my basement. Now off to search ‘does oil expire’. I could not resist the sale + rebate.
I would use 2 qts of each and have 2.5W25 this way all will be happy.
Heck I remember in '83 Civic in Potsdam, NY when it was sub zero often I was happy as I had dropped down to 10W30 from 10W40. I don't even know if 5W or 0W were an option then. I think Mobil 1 was the only really synthetic that was out there. It was a lot more than the dino's. I also ran a plain Fram orange can. It survived.