I use helicopter rigs for 90%+ of my fishing and very rarely suffer hook pulls. I notice you said you don’t have a history for hook pulls before, so did they start when you started using the hinged stiffy or choddie? Do you use the hinged stiff rig with a “traditional” amnesia/stiff boom, or with the “soft” booms, coated braids etc? I understand their use - to allow the hook link to rest naturally over the choddy substrate, however perhaps the soft boom gives the carp too much rope? With the amnesia boom, the carp usually prick and hook themselves on the weight of the lead immediately. Worth a thought.