From my understanding or what i have heard, it takes at least a month to get visa from Canada for USA. So, my friend she went mexico twice during her undergrad and got visa stamping. One of my frn's friend who tried to get visa stamping from canada was deported. (I am not sure about the reason). But all i heard is, its not easier to apply visa from canada as it was back in the days and so people are going to mexico for that purpose.
... Hope this would help N all the bst for what u doing..