Omaharj:
You might consider borrowing a method from the bench rest rifle shooters, w/slight variation.
That is, use a pistol bench rest. Lohman (and others) makes a Pistol Sight Gun Vise which solidly clamps the pistol barrel (revolver) or frame (semi-autos). Gives the handgun a solid, consistent sight alignment/picture while sighting in and shooting. The shooter sits while squeezing them off, similar to a rifle shooter.
Using this device takes most of the wiggle out of aiming and minimizes the effect of poor trigger control. Helps to determine if it's the shooter or the pistol sights that need adjustment.
This device would be useful for every firing range and gun club, just like the shot bags and benchrests used by rifle shooters.
sfg