I've been using circle hooks for carp fishing for probably at least ten years now. I've used them with sweet corn right on the hook and with hair rigs threaded with sweet corn, field corn, artificial corn, and boilies. I've almost always used Gamakatsu Octopus circle hooks, e.g.,
I get occasional hook pulls, but not very often. If I'm getting hook pulls, it's usually because I'm using a smaller size than I should for the fish I am catching. I like the above in size 2 for larger carp, and size 4 for 12 pounds and under. Every hook is set perfectly in the corner of the mouth, making hook removal in the net easy before I even bring the fish out of the water. I've never had a hook set anywhere other than the corner of the mouth or the lower lip.
They are also good for when I get a run and it takes me a little while to get to the rods. I don't have to "set" the hook with these hooks, they are already in place just by the bolt rig or the resistance of the reel drag.