You can get a LOT of food into a Bear Canister. Even though the Bearikade is way too expensive this video gives an example as to how much can be loaded.
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The weekender shown is 650cu/in. The Bearikade Scout, UDAP, and Bear Vault 450 are not that much smaller (about 500cu/in) and can certainly handle the trip you described without repackaging. Repackaging will gain you room for sure but only do it if you need to.
I just got back from the Bighorns. We used a 650cu/in Ursack. We packed in 5 days and 4 nights of food (un-repackaged Mountain House, Backpackers Pantry, Alpine Aire and Mary Jane's Farm) for two people. All the meals plus bars, snacks, tooth brushes and toothpaste and any other odor producers fit into the bag. With room to spare....
As pbakwin suggested we are planning to start to package our own dehydrated food. It's a pain but it helps the cost, you make up what you like and it packages smaller. Of course the cost is time and hassle when you'd rather be outdoors
The pin hole idea is a good one. I'll be trying that myself.