ok watching this video i think you need gun technique practice. i see you going over down and back without ever releasing the trigger. i think you should practice going straight across and off the fender concentrating on your speed,distance and overlap. the way you are doing it some spots get a much heavier application. if you dont release or go off the fender at the end of the stroke for that second when you stop,go down and switch direction you will be overloading that spot.
you should also be doing the leading edge of the fender and the wheel well lip and other hidden spots first.