I would be interested in feedback from those who shoot an O/U with an adjustable rib. I know there has been considerable debate regarding the real value of an adj. rib on an unsingle...but, I wonder if any of you have really adjusted the rib to move the POI on either the over or under barrel. Could you really make a back up to your unsingle, by adjusting the POI of the O/U to match the POI of the unsingle. Or, what is the real purpose of having an adj. rib on an O/U barrel. Thanks for any input.