Personally, I think the HD single disk opener as you are using on the 1560 will do a better job of handling cornstalks at an angle as you are doing. Metering may be a bit better on the Case units but doesn't really mean much if you can't get a consistent seed slot.

I am probably in a minority here but if you are looking for a significant improvement over what you are currently doing I would look for a 30" Case 955 put Trashwheels on it (our smaller sweptback tooth wheel works especially well in this situation) and just notill your beans down between the old corn rows parallel to the rows. This works especially well where you have left the standing cornstalks tall. jmho.

One other advantage, you can probably buy a 8R30 20 ft or 12R30 30 ft 955 and put row cleaners on it for about the same money as a 15ft 5500 or splitter planter. You will also probably be able to significantly reduce your planted seed population (and seed cost) with a 955 compared to the 1560 or the 5500 with seed cups. Good Luck.

Jim at Dawn