Mike,
This won't give a quick fix but will help you determine a measurement.
Make a "rib" as long as the barrel out of wood, 1/4"X barrel lenght X 1/4. Cut a kerf across each end. Sand one side to match the barrel contour. Attach the rib, centered, to the barrel with stout rubber bands. Put the bands in the kerfs so you don't see them when you mount the gun. You can make several of different thickness to stack on this rib. Experiment until you have one, or a combination that looks "flat" down the barrel. Measure the height the rib extends above the reciever, this is a rough idea of the amount to remove from or move the top of the stock.I caution you, this is a rough measure. You will need to go slowly and mount/shoot the gun into a marked target to see your POI, adjust accordingly.From this point other factors will come into play, how the stock meets your face/ shoulder etc. Hope this helps.
Rick
