One last comment on this hitch mod. We came out of a parking lot on our last trip and the hitch, with bikes loaded in it, scraped the payment and took the exposed "tightening bolt" right off. When I got home I was lucky to be able to pull out the 1.5" bike rack, but had to cut out the 1.2" to 2" plastic adapter, then mm by mm unscrew the bolt from inside the hitch, then cut the damaged part off with a sawz-all, and then was finally able to remove the remainder of the bolt.
So, bottom line, this optional refinement to a rear hitch may not be worth the potential trouble!
Oh, and the welds are still holding tight!