Remember, the rules say your food for the current day does not have to be in a canister. I suggest an odorproof sack. That automatically reduces your canister load by one lunch, one dinner, and whatever snacks you'll use. It's not much, but it can make the difference in canister choice.
I have a Bearikade Expedition and have used it for years on the PCT, most often but not exclusively in the Sierra. It is a multi-duty item – bear canister, camp stool, camp table, secure FLAT base for my stove (I can strap my closed cell foam camp pad ¾ of the way around it as a tall, secure windscreen). As space becomes available inside the canister, I move other items of gear into it, freeing up pack space inside or out.
How many days’ food will any given canister carry depends entirely on what you’re eating. The only way to know is to try one. REI sells the BearVault (BV450 Solo and BV500) and the smaller black Garcia Can. You can always return the one(s) that don’t work. I seriously doubt that either the Garcia Can or the BearVault 450Solo will be adequate for you, especially if you’re carrying for more than 5 days. I’d say start with the BV500….and see if you can borrow an Expedition from someone local on the forum.
The BV500 is much cheaper than either of the Bearikades (Weekender or Expedition). The Expedition is the largest capacity, lightest canister made, but at $275, it is spendy. If you anticipate using it more than just for a single trip, it is worth the extra bucks …..IMO. No, I don’t work for Wild Ideas. I’ve seen and tried the others and I’ll stick with my Expedition.
Incidentally, you can also rent one direct from Wild Ideas. See http://www.wild-ideas.net/rent-a-bearikade
As noted by another responder, you can rent bear canisters from the rangers in Yosemite Valley and Tuolumne Meadows. They have mostly Garcia Cans and a smaller supply of Bearikades. As far as I know, its first come, first served.
From your post, I’m assuming you will be starting from Yosemite Valley and going south to Whitney Portal at an average pace of 10 miles per day.
Your possible resupply points will be:
1 – Tuolumne Meadows – 25 miles from Yosemite Valley
2 – Red’s Meadow – 34 miles from TM
3 – Vermillion Valley Resort -29 miles from Red’s Mdw…… OR….
4 – Muir Trail Ranch – 20 miles from VVR
5 – Onion Valley/Independence via Kearsarge Pass – 68 miles from MTR + 9 to OV
6 – Whitney Portal – 41 miles from the KP trail jct.
It’s a long, hot climb out of Yosemite Valley. While it is possible to skip the resupply at TM, it is not advisable. Why carry all that extra food weight needlessly? Make it easy on yourself. You can fully resupply at the store at TM or send yourself a package to the PO there.
Red’s Meadow is a must-stop; cold drinks, a great café, shower and laundry facilities. Besides, you’ll need it.
Going south, there is no need to resupply at both VVR and MTR, as they are only 2 days apart. I would suggest you carry 5 days’ food out of Red’s Mdw and skip VVR (29 miles south of Red’s Mdw) entirely. It is 6 miles off-trail if you walk or, depending on the water level in the lake, a 1 or 2 miles walk to the ferry landing. Resupply at MTR instead (20 miles south of VVR). It is a mere 0.5 miles downhill off-trail and a gentle 1.5 mile connector that takes you back south to rejoin the JMT. It means carrying 2 days less food from VVR if you were to skip MTR.
From either VVR or MTR, you have a decision to make regarding resupply.
Option 1: Onion Valley Pack Station: Leave the JMT at the Charlotte Lake/Kearsarge Pass Trail junction. Hike 9 miles over Kearsarge Pass and down to Onion Valley. The Sequoia-Kings Pack Trains station (800-962-0775) will hold packages for you at a cost on par with MTR) or can deliver them to you at many places on the trail (prohibitively expensive unless you’re a group). You can also get a shower at the pack station for a small fee.
Option 2: Independence or Lone Pine: As above, get to Onion Valley. Hitch a ride down to Independence P.O. or better yet, catch the bus from Independence to Lone Pine and resupply in a full-service town. Reverse to get back to Onion Valley. There is a commercial shuttle service in Lone Pine (http://www.mtwhitneyshuttle.com) that will also take you back, but that’s about $90 one way.
Option 3: There are restrooms, potable water, and public bear boxes beside the main parking lot at Onion Valley. You could leave yourself a resupply box in one of them, but they are out in the sun all day and are not secured. Better to have a friend drive in and meet you at the USFS Onion Valley campground (~$20/night).
Option 4: Skip Onion Valley entirely and carry enough food for the final 109 miles (11 days). You’ll need the large Bearikade Expedition canister for that, plus you’ll be carrying a lot of weight up and down the 5 major passes ahead of you. At least your pack will be getting lighter with each meal.