well i can safely say because gunners classed into aa dont get good reload and thats what you need to spam aa towards planes personaly im using 2 huge reload gunners with almost full experts and 120 vets each with the lvl 18 3''/70 cal mark 23 D
they have 1.08 reload speed which you will need to fast spam alot of AA hehe im liking this one its doesnt take much space and it holds enough ammo for alot of planes