The difference between 60-40 and 50-50 is three inches at 40 yards, less at lesser distances. This is no difference at all in practical terms. What makes a difference would be a 100% above the point of aim. Another thing that makes a difference is the comfort level of the shooter's view over the barrel. Some people just can't stand to see a bunch of rib, others can't stand to see just the bead. I personally can't stand to see much rib on anything but a rising going away target like a trap target. Even the stocks on my trap guns that I use for sporting clays are field dimension so I can be "one with the beads". By the way, I have learned to ignore the drop at heel dimension which is not of much consequence. The drop at face is the one that is important.
