The Garcia is not easy to source in Canada, whereas the BV500 (10.6L version of the BV450) is available at leading stores. I am currently leaning towards the BV -- translucent + ridges to channel tie downs.

Good question. For the trip I have in mind ATM, if I am lucky (i.e. stores are open and accept business from travellers) 1 or 2 days of autonomy should be enough, although I tend to eat oatmeal for breakfast which means a scented food source for the duration of the trip. I would go for the BV500 in order to be able to store close to a week of food, and because its longer shape should prove easier to stabilise on top of the rear rack. (I also have in mind a month long trip where, for now, I have a little notion of the maximum autonomy I'd need. One week should be enough).