My P229 40 SW came equipped with the standard contrast rear sight #8 and the white dot front sight #6. I am shooting 6 inches low at 20 yards using factory ammo. Which sight should I change? The front or rear. Most important what number should I change too. I cant find any information about sight heights and how it affects Your point of aim/point of impact. Its a nice gun, but is just sitting there because it is frustrating holding the gun at the top of target trying to get one in the bullseye.