Gosh, I am very sorry, Gimley, that my concern disturbs you. Perhaps you are one of those who really do think there is such a thing as a dumb question.
It just happens that I have never seen a HiddenHitch in person and am trying to find out from people who know. From the photos it looks pretty lightweight to me.
When you add six inches of leverage to the (seemingly) rather modestly built receiver with the adapter, that gives the adapter plenty of additional leverage to work against the attachment point for the existing 1 14" hitch. That is the TORQUE I am concerned about. Torque is the power to TWIST--in this case, to TWIST the 1 1/4" receiver relative to the hitch frame. Also, if you think the load back there is a STATIC 200 lbs or whatever, then I envy that you are lucky enough to drive on perfectly smooth surfaces with no speed bumps, chuck holes, etc. Unfortunately, I am not. It also looks to me like you abslutely do not understand the difference between tow weight and tongue weight. Tow weight is HORIZONTAL. Tongue weight is VERTICAL.
Tell you what: You call HiddenHitch and ask them how they feel about adding an 6" long receiver adapter to their hitch. I am glad that you have been successful with this arrangement and appreciate your relating the experience. I know nothing about the Thule rack but the Yakima is physically pretty heavy, so pardon my concern. No offense, but your apparent contempt here for someone asking a couple of questions seems to me to be a bit much.
regards, yelapa