I faced the same situation with a 2388 without tracker, single wheels, only with a 30' 1020.  I considered putting the tracker on, but instead applied the money that that would cost to a MacDon head.  On my ground that eliminated the need for field tracker, and the combine seems like a completely different machine in soybeans due to the even feeding.  I don't know what a 3020 head would cost, but consider spending that money and the money for field tracker toward a draper?  May not work in your situation, but something to consider.