Here are the rules:
If Country not Canada, then 0%
Else Canada so please see the table "Tax rates per province/territory" at the link below and use the total tax rate percentage in the rightmost column.

https://canadabusiness.ca/government/taxes-gst-hst/federal-tax-information/overview-of-charging-and-collecting-sales-tax/ 

Note that these taxes are not related to the customer's credit card location, but to the customer location they enter in the signup process.

I will send you a separate issue detailing any needed tax rate corrections for our existing customers. Expect that in January.
