Thanks for such a detail reply, Larry. OK, I see what you mean. When I scrolled forward to the last page, I saw the images you're referring to. There was one there that I also found simply spectacular:
I don't have BushHawk but I did try using a similar shoulder support brace made by Leica for their Telyt f/6.4 400mm and 560mm lenses that I had "leitaxed" to mount on my D800E. They are quite a bit lighter than the 200-400 Nikkor and designed to be handheld. This is as sharp as I was able to get it handheld using manual sliding focus on the 400mm lens at maximum aperture:
I am still not fully happy with the results though, so I'll have to keep playing with various ISO/shutter speed combinations.