The "Straight Eights" are said to be properly sighted when the dots are stacked forming the figure 8. I loathe dot sights, I solve the problem by replacing the front sight with a fiber optic, or painting the front sight a bright orange. For me, the only way to get a precise sight picture is to sight in at the top of the front sight. The front sight dot is about 1/3 of the way down the sight.
Savage