See, I'm not that concerned about Canada being a bit behind the US in terms of M3 deliveries.
Elon has basically all but confirmed that Tesla will manipulate its deliveries to ensure the maximum number of M3 buyers get that tax credit. That means Tesla needs to deliver their 200,000th car in the US on the first day of a quarter.
Thus, unless that happens by chance, there will be a period of time where Tesla can't deliver a car in the US without triggering it. The options then, are stockpile cars until the quarter ends, or ship them internationally. While I do believe there will be some stockpiling, Tesla can't afford to tie up too much capital in finished product, so I suspect that the majority of those cars that can't get shipped to the US will come to Canada, as its too complicated to get them on boats to go overseas. Additionally, so far as any of us know, there are 373k reservations, and a factory that should have a run rate in excess of 500k cars per year. I estimate only about half of the reservations are US reservations, so in 2 quarters, they should be able to deliver all of the reserved US cars, even accounting for some ramp.