RE: Problem with flinching
I would suggest getting a PAST recoil pad that slips on and off your shoulder over your clothes. Go ahead and get the Mag recoil pad. Will make bench shooting much more enjoyable.
2-3 inches off at 200 yds? This could easily be a parallax problem. If your scope is not parallax free at this distance then you and your dad could be looking through the scope differently. To see if it is parallax, set the gun up solidly in a rest w/ the crosshairs on the target. Without touching the gun move your head back and forth past the eyepiece and see if the crosshairs move on the target.
But if you are shooting good consistent groups with it, adjust the scope for you and go on.