Thanks for posting this. This is really good information.
A couple of questions:
What type of phone(s) are you using for your Sims? I know you need a phone with the ability to switch to WiFi calling. If you take an activated SIM card (activated from the US) to a Thai phone shop will you be able to pick up a compatible, cheap phone that will be capable of accepting texts via WiFi calling? I would think from Thailand you would need both a GSM and CDMA compatible phone, that is unlocked, that has WiFi calling capabilities, that uses a standard Sim size, right? Or is GSM alone fine? Any ideas on a cheapy phone that fits the bill as I would probably only use it for SMS sent from the States, primarily for 2FA.
My current phone uses a nano Sim and the U mobile sold on Ebay is a standard SIM. I guess I'm looking at having to find a compatible phone in the States that can support that SIM in order to activate it. I wonder if that is where I might be better going the US mobile route.
Also, all of you're backup SIMs have their own phone numbers, right? I'm guessing that any website where you need 2FA has your primary number and then you've listed a couple of your backup numbers with them? Or are you using other methods for backup in case the primary number does not work like an authenticator app or security token?
Thanks for any help.