We have been pulling 4 wheel header trailersfor a number of years. The "Spreader" chaff spreader co. of Gifford Illinois makes a hitch right on the back of their spreader.It works ok not too heavy duty though.
We just got an old draw bar and bolted then welded (extra stranght) to the back under the chaff spreader on our 2188 Axial flow combine. We also welded a metal bar under the draw bar for more support. Now we can tow our Unver. header wagon with our 30ft grain head on it.