I made that mod and posted it on this forum sometime in 2018.
Performance was alright, nothing intensive was needed to be done.
I am not sure whether defining quadrants will be an issue. What I did was take the relative rotation of two entities in attack, translate for attack direction if needed and just take the circle quadrants based on angles.
I recall having to revise it to only take the relative rotation of attacked and the attack, because missile attacks can have vastly different attacker and attack orientation depending on projectile speed.