My research on handling shows different shooters have differing sensitivity to the handling parameters. Some are sensitive to weight, some to balance, some to unmounted swing effort and others to mounted swing effort. Very few are sensitive to all. Awareness of the parameters and handling guns of known values usually increases detection sensitivity. The sorta average range of sensitivity I've found is about 4 ounces of weight, 1/4" of balance, 0.20 unmounted swing effort, and 0.4 mounted swing effort.

I don't yet have any good average data on what measurable difference handling numbers and stock dimensions make in shooting scores. At some level, I'm sure they do. However, I can say that most people enjoy shooting certain guns more than others. Enjoyment of shooting is, IMO, equally important to shooting well. Therefore, I consider finding guns you enjoy equally important to finding guns you shoot well. Magic happens when a shooter finds/has made a gun he truely enjoys and shoots well.