Hi,First, stop using the 3 pt drawbar for pulling trailers, there is mo down pressure on the 3ph other than the tongue weight. It is a good way to get into trouble. Use the fixed drawbar attached to the under belly of the transaxle—this can not raise up.
Second find an opened area and get some flags—the ones on a thin wire. Then practice practice practice. Then practice some more. You must think in a different way from backing up a trailer when backing up a wagon.
Not using the 3-point...using the draw bar. I was asking if I should use the 3-point arms to keep the tongue perpendicular to the tractor, making the wagon pivot the only pivoting point.