Ben,
See this video,
http://www.andersenhitches.com/Catalog/andersen-nosway-weight-distribution-hitch.aspxIt shows the tapered ball shank coming right up out of the shank socket.
Now to the coupler... OK you saw something I did not. The gray mocked up frame has no latch....duh???
But in that same video you can see a Dutchmen TT on the back of a F250. The Dutchmen has the standard TT sliding latch. I think the gray demo frame is a computer model and not a good on at that.
OK now I know what you mean by safety pawl. Are you saying the WD forces on the tow ball are going into the back half of the coupler into the safety pawl? If so, I didn't see it that way. I see them going forward into the front of the coupler sphere. Trying to make sure I understand your thought process.
Still typing my thoughts on the hitch..
John