It all depends on the gun. Two different guns with the same stock dimentions may not handle or point the same. I recently picked up a Wm.Evans about 14&1/2" cast for left hand , that came up for me a right hander as if it had been made for me. Compared to a new AyA No2 with a 15" straight stock that should have fitted me better {6' and long in the arm} but it did not seem to fit as well.
You can not realy take the measurements from an O/U and transfer then to a SxS or vice versa ,becuase of the difference in the guns . Each has its own set of requirements , apart from basic left or right hand and aproximate length.
