My first suggestion is simple, and is made for non-fighter aircraft that engage in dogfights. What if instead of being aligned with the cockpit crosshair to fire, each gun had a 1-2mi long firing line. And Activation Groups assigned to only guns will auto-enable when an enemy aircraft is in their firing lines, then auto-disable when there is nothing in the firing lines.

My second suggestion is an AI type that attacks only aggressive planes, and ignores player & passive AI fire. This suggestion would be easier to add, and can simply be done by copying the aggressive AI code, and then doing some replacing, adding, and removing scripts.