1. This is very easy to do using a load rule. Simply create a load rule that says "domain(dom) -> contains -> oursite.ca" OR "domain(dom) -> contains -> oursite.jp"
Assign this rule to the SiteCatalyst tag, and it will only fire on these 2 domains.
2. There is no way to know how many times a tag has fired, because the Tealium utag.js is client-side and does not have access to any data, except the data that forms your data layer (cookies, query string, data object, meta tags etc.).
You could, however, use the Tealium split segmentation extension (https://community.tealiumiq.com/posts/554741)
to only fire the tag for X% of your visitors. Have a read of that post and let me know if you have any questions.
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