Okay so it's not entirely my fault. I came to the same conclusion about the rear hanger, that it is oddly attached to the bumper bracket. That said I have a NOS (c1970) ABARTH rear resonator that is due to go on my wagon when I get to it. It came with a hanger that, like the Simon's, hangs from the bracket but is way more sophisticated. It has two plates that straddle the bracket with bolts top and bottom to secure it, then a nice steel thingy that the resonator hangs from.

Could the tension on the donuts be evened up by rotating only the amid ships pipe? I did do that, it worked, but did not ease the closeness of the pipe to the floor.