First of all, as has been stated, there are some places in National Parks and some related wilderness areas where there is no legal substitute for a canister. For ten years now, I've used one or the other brand of canister without fail when in those areas.
Prior to that period, I always did a proper "bear bag hang," and I led group trips for twenty years without fail. The technique was a counterbalance, mostly, but with a second rope. I always used the second rope, and its purpose was purely to pull down the first food bag from high. 1.You throw the rock with one rope end over the branch. 2.You tie the first food bag to the rock end of that first rope. 3.Pull on the other end of the rope to get it started. 4.Before that first food bag lifts off out of reach, you use the second rope. 5.Simply loop (no knot) the second rope around the top neck end of the first food bag, and leave both rope ends (of the second rope) dangling, or held by somebody. 6.Now, with the opposite end of the first rope, you hoist the first food bag high to the branch. The second rope ends are still dangling from the food bag. 7.From the hoisting end of the first rope, reach up as high as you can and make a slip knot loop and insert a mini-biner into the loop. 8.Clip your second food bag into the mini-biner. Then take the excess rope from that end and stuff it loosely into the top neck of that food bag, leaving two feet of rope exposed. 9.In that two feet, you tie a bowline and leave the loop exposed just barely below the bottom of that food bag. 10.Now go back to the second rope with dangling ends. Pull both ends simultaneously, and that end of food bag will descend, which elevates the second food bag. 11.Pull it until the two bags are level, approximately ten feet off the ground. 12.Then, with the dangling ends of the second rope, you pull carefully on only one end. It will pull around the food bag and fall off. Now you have no ropes dangling down with the exception of just a little bit of rope loop below one food bag. You're done.
In the morning, you grab a piece of tree branch and reach it up to snag the exposed bowline loop. That pulls the excess rope out of the food bag neck until you can grab the rope. You pull on that end until one food bag has descended within reach. You unclip it from the mini-biner, then use that rope end to lower the other food bag.
If you paid attention to this, you will notice that the branch needs to be more than double the ten feet, so figure on 25 feet. Notice that it takes a pretty good baseball throwing arm to chuck the rock and rope up over that.
If this sounds complicated, it is for about the first three practice sessions. Then it works fine. I never lost any group food to bears, especially the wily Yosemite black bears.
Aids: after dinner, tie your washed cook pots and pans around the trunk of the tree at a height of about 5 feet. In fact, tie any other metal sporks around them to be the noisemakers, so if the bear tries to climb the tree trunk, you should hear the metal. It helps if you sleep right at the base of the tree trunk.
Decoys: take an ordinary paper bag (empty) and tie it up with some nice bright cord, and hang it carelessly from the wrong tree. The bears will fart around with it to give you enough time to wake up and defend the correct tree. The park rangers can't cite you for that, since there is no food in that decoy bag.