Hi ​@naanfan - thank you for reaching out to the Klaviyo community with your question!

I would personally recommend keeping one main email subscriber master list and using the Klaviyo flow conditional filters to run one singular welcome flow that has two branches, one for US and one for Canada. This way you are able to track overall email list growth and welcome flow performance in one instance vs. having 2 lists and 2 flows. 

Using the Klaviyo conditonal filters within your flow is simple to set up. Here is a screen shot of how this would look in an account. This help article explains flow branching and conditional filters in more detail as well.

From here you can continue building out each branch of the US and Canada welcome flow messaging series and also decide what you want to do if a customer comes through and neither of those countries are true. Do they simply exit and not receive anything, or is there another branch of generic creative for any instance where the country may not be defined?

The two solutions you recommended would also work just fine, you would just be managing 2 lists, 2 segments and 2 flows. This could absolutely still work for what you are trying to achieve, but let me know what you think of this combined solution using branching as I think it may save you some time in both setup, reporting and monitoring performance!

Depending on how large the creative differences are between the US and Canada emails, something else you could consider to consolidate even more is using the show/hide logic in the template builder to show or hide US or Canada specific blocks within 1 email creative based on the person’s country listed in their profile property. You would set up sections or blocks for both Canada and US in 1 email template, then within each of the blocks add the logic to only show the US blocks if someone’s country equals United States or only show the Canada blocks if someone’s country equals Canada. This help article breaks down more details about the show hide logic in email templates if you need it! 

Please let me know if you have any other questions as you are setting up your new welcome flow. I am excited to hear how it goes. Thank you again for reaching out to the community!