Not a trailer tongue but this Saturday had to hook to disk left in field for blow line. Was wondering about rehooking by my self in soft and backed up as close as I could with no help, pulled the draw bar pin and pulled it out an inch or so needed to pin the disk. Then I wondered now how do I line up that much tighter draw bar pin to tractor? Thought maybe I can move very slowly and the draw pin will drop in place...well it did and was latched when I stopped. I moved very slowly and realize when the disk first moved stopped and backed us a tiny bit and it moved back.
The pin for the draw bar has a strong taper on the end and is weighted so it lines up and fell into place very easy. The design of the latch locked the pin in by the dropping of the pin. I had wondered why such a latch design for my Kubota's used a pin and hair pin to lock its draw bar. Who ever at John Deere came up with this seeming odd design sure got a thank you from me Saturday.
You may need to weld a bushing to give it enough length to keep a pin lined up vertically but you should be able to taper a pin, place in the top and with trailer hooked slowly move in or out with tractor and the pin drop. You may have to wiggle it some for there is a lot more distance with no guidance in your tongue than a JD draw bar.