I use them frequently for BSA outings. Typically 2 – 3 people for 2 – 3 days will fit in one canister. I have fit enough for 7 days and six people in 4 cans. We usually fill any voids with toiletries and types of trash with scents. Doug at the Portal Store provides a great service by selling the canisters at half the cost of our outdoor retailers at sea level. I ended up purchasing, but mine see a lot of trail time. Rangers on the trail have asked to see the cans from time to time. The weight is a bummer but it is comforting to know that your food can be left unattended and still be there when you get back. I usually like to wedge it somewhere or put a rock on it to keep the marmots and bears from rolling it to far away. Just a tip, as I use the food I fill it with other stuff to shrink my pack whatever little bit I can.
Have Fun.