Hello, I'm hoping for some advice please . I own a number of spring rifles which have factory or aftermarket adjustable butt pads fitted . Is there a means of determining the optimal position for the pad , or is it just trial and error to determine what feels best and produces the tightest groups ? I shoot Sft sitting , standing and kneeling . The reason for my question is that i've recently ressurected one of my older rifles and it groups much better in the vertical plane than horizontally , could the butt plate height be an influence on this please?