Gave up on expecting any kind of notice and called the support number. Gave them a card number and a PIN code, they said they will be doing the transition this week but can’t be sure how the Ambassador line will translate. I’ve changed my mind on tactics for Canada testing. I have put the RW/DISH/BoostInfinite SIM in my old Samsung Galaxy A11. I’ll be taking that to Canada with me and we’ll see what happens. Based on prior history and the somewhat confused responses from support, the expected result is: No Service.
This way I’m running two Canada tests at the same time. For details on that, see this thread.