Mr. Bubba,
your choices look solid to me. THe 8411 is a great servo and if you have them already, I say use'm!~). The 80 would be insane but heavier. Either way you are in for a good time. I believe the standoff size is 3", DA is just a call away and I am positive Brian Hueffmijer knows the correct size.
If you stick the 80 in yours I might have to stuff a DA100 in one!!!
Joe