ok--how's this for wierd: i'm right handed, right eye dominant, but i am extremely nearsighted in my right eye, and 20/15 in my left. ergo, for practical purposes i'm left-dominant, but anytime i'm dealing with something within about 30", my right takes over. long guns aren't a problem, either because i'm using an aimpoint w/ both eyes open, or the eye relief of the scope/irons are so close that my right doesn't try to refocus on them.
pistols are another matter. if i'm not concentrating, my right eye will take over and focus on the rear sight, leaving everything beyond that out of focus. i didn't like the idea of closing one eye while shooting pistol, so i came up with an alternative solution. i now shoot weaver, and turn my head about 3-5 degrees to the right. voila.
i prefer to change the position of my head rather than changing the position of the pistol, because i maintain a natural shooting posture and weapon/body relationship. in addition, it's a lot easier to reprogram muscle memory for one group (neck) than for several (hands, arms, shoulders).