I think the key question is whether you want to own a bear canister --- i.e., that you anticipate enough additional trips where you'll want/need one to make owning and storing the bulky thing(s) worth it --- or whether you just want one for this trip only.

If the latter, I agree with Lori, rent bearikades.
If the former, then it depends on how MUCH you plan to use a canister in future. If the answer is "a whole lot", I'd step up and buy a bearikade. If not, I'd go with a BV500 (which IS the bigger version of the Bear Vault line --- I can't imagine carrying a canister bigger than that).

If you can't fit it all into a BV500 (one per person), then reconsider your resupply plan and/or study and practice at getting more efficient at what you can fit into the can (it's part science, part art).
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Brian Lewis
http://postholer.com/brianle