Here's a couple shots of the bottom of the extension. These are as good as its gonna get without pulling the extension out, and to do that I'd have to remove my carpet and the inner boots so I don't see that happening in the near future lol.
If you look closely you can see the gusset welded to the frontal part of the extension. I had to put it there because the 3/16" steel alone would bend while moving the lever into 4LO. The gusset runs from the bottom of the extension up to the bottom of the fx4 shifter, not quite to the top of the extension. It took quite a bit of trial and error to come up with something that wouldn't bend and would fit at the same time.