Matt, I've shipped to Canada and had to fill out a customs declairation form. On the items I sent( staves and raw shafting) they were "craft" items and "gift" with "0" value. All true! I don't know how it works coming this way but I have gotten raw materials from an individual in Canada.
You might pull up the Canadian Post Office website and see if there isn't something there about it or drop by your local post office and ask and pick up any forms you might need before shipping.
Marc St Louis ships bows all over. Maybe he can tell you how he does it.