I don't know if this has been stated already, but even if so, it is important enough to remember that I will state it anyways:
Bears can climb trees, and they have learned how to deal with ropes. Believe it. They are very smart and just as agile. The only sure way is with a canister, and keep it a safe distance from where you sleep, outside of your pack. Don't hang anything, as bears can get it and at the same time damage the tree. They might even go the route of severing the rope by chewing. Again, bears are smart.
Don't use canisters inside bags, as they can be carried away, and even though the food inside is not gotten, you may find it difficult to track your food to its new, bear-chosen location. Even the smartest bear will feel less than motivated to roll a canister to any considerable distance. If you think canisters are too heavy, then reorganize your pack list by eliminating something(s) of equal weight, so that you do include one. Besides, at a couple of pounds, they are not too heavy. Toughen up, ultralighter.
Ultimately, we are all responsible for maintaining that our wild friends remain wild. Canisters do not reward hungry bears in any way, and that's how they learn to avoid human camps as food sources. Non-food items that they smell might still attract them, so you might want to canister those things too, but bears are ultimately only there for calories. If their hunger is rewarded by raiding a camp, they will do it again. A bold bear is a dead bear. Let them remain wild, free, and alive.
Your food source should be thought of as secondary to the health of a wild ecosystem. We are all guests of the wild, while in the wild. Please keep it, and rememeber that.