I have a very similar one from Modern Implements 7 FT with the hinge back, only difference is mine has the manual scarifiers, mine also is a category 2 hitch. I bought CAT 1 to 2 bushings from TSC, and cut them down to where the were flush with the hole on the inner ears. Then I bought CAT 1 pins with the bolt ends, I mounted the pins inwards and bolted them through the first set of ears with grade 8 washers. It is not the preferred method but I haven't had any issues. I will post a pic tomorrow when I get home. I have noticed after about 25 hours one of the pins is bent by about a half inch. But considering all the stuff I push and pull with it I guess a little bending is expected.