I also vote for absolute co-witness. I find the lower 1/3 confusing when trying to get off a quick shot. The circle within a circle of the absolute cowitness is very similar to the sight picture used by 50 meter (and other) small bore competitors. They use a target with a X-ring smaller than the diameter of a .22 bullet and consistently clean the target. Your eye will automatically align the rings concentrically without any conscious effort on your part.