We have been using the Shopify Connector successfully for a couple of months with customers synched to a generic, per country account.
Shopify calculates VAT for the "ship to" (not the "bill to") country (this behavior is correct as VAT should be applied to the country the goods are delivered to). When using a Default Customer No. per country (under Shopify Customer Templates) allows for the correct VAT calculation in Business Central even in more complex scenarios for customers being delivers in another country. For example, Business Central will correctly use the French VAT Bus. Posting group on a sale for an Austrian customer that is delivered in France or doing a "Pick up in store" in France.
However, because we wanted a more detailed follow up for our customers, recently we switched to using a Customer Template per customer (now we create a customer in BC every time an order is imported from Shopify). The customers VAT Bus. Posting Groups are created correctly in BC. However, now we have an issue with customers that shipped to an address in a different country (I was surprised, but we have a few). In this scenario, our Austrian customer that is shipped in France, is still charged VAT in Austria, causing us to review and correct a few invoices.
Anything else I am missing? Thanks