Does anyone know how much of a difference in POI the marks on the inside of the ghost ring ears make? I shot my 590A1 at 50 yards today using slugs, and it was right on for windage, but they were a bit low. I ran out of slugs so I couldn't actually zero it, but once I got home I did move the ghost ring aperture up one "dash" to move the POI up a bit. Does anyone know how many marks I should move it up to get roughly centered at 50 yards? The manual didn't say. I was shooting using standard federal rifled slugs. Don't know the weight off the top of my head.