I also asked this question a couple months ago, and the consensus was not
to add the bike rack receiver... "may" be OK, but not worth the risk. I had previously done this on an old popup and worked great, but elected not to do on the new TT.
IMHO... If you still want to proceed with the hitch, I suggest replace the bumper with a heavier grade steel and have a knowledgable
welding shop create a custom receiver that is welded directly to your TT frame in a way that evenly distributes the load... remember, your bikes will bounce like a diving board creating a lot more stress than you think.
Instead, I upgraded TV to a pickup truck... problem solved.
2012 Ford F150 4x4, 5.0L, 3.55
2011 Rockwood MiniLite 1809s
E2 WDH 600/6000lbs