Good move to ditch the hitch!
Welcome to the forum, and congratulations for doing your research thoroughly. Good to have you aboard.
You might be interested in reading these threads about improper rear loads, which can cause sway problems, some out-of-control:
http://www.airforums.com/forums/f48/...ec-153984.html
http://www.airforums.com/forums/f238...ay-152451.html
The first thread linked above concerns a roll-over wreck in Quebec, and although the thread is long, it makes for a good read IMO. If you look carefully at the photos, you can just make out a hitch receiver similar to yours.
Happy Trails!
Peter