Speaking on behalf of the Australian side, you have a maximum landing value of 1K before being open to a 10% GST. Now, of course if you are talking about shipping individual orders from Canada itself, then GST isn't going to be an issue for you.
It really comes down to what sort of stock load you are carrying as to what options you can choose from in regards to a distribution model. Low or no stock supplier method would give you no choice, orders would have to be shipped internationally item by item from Canada.
If you are dealing in decent stock volume, you have far more flexibility in designing an effective distribution platform!
For example, there are advantages of actually selling from within the countries that you market to over and above selling into them internationally. That requires you setting up some sort of a store and send platform in those countries, but as I said, it can be beneficial doing it that way.
What you need to do is set out a business plan, a road map of where you are now, where you want the business to be in 5 years, 10 years, 20 years and what processors you need to put in place along the way to make that happen.
Getting a plan down to begin with gives you long term direction, super important to long term success. Those that tend to make it up as they go along hit all sorts of bumps along the way, most of them unseen, and most of them cause a derailment because their is no process in place to ride them out.
I always say that research is king is this online game, but good planning is no court jester by any means!