For sure things change over time. We have better information right now to draw upon.
One thing that didn't change with time is:
Whatever Willie did, he did it better than anyone at his time and he did it more often that anyone...........SPF=randyg
Perhaps he wasn't good at putting down on paper his expertise, but I'm reminded that Einstein said nobody else really understood his theory of relativity despite his best attempts to explain it.
And my old eyes aren't the best but it looks obvious to me at :36 of this video that Mosconi uses a little slip stoke. Not as exaggerated as Jimmy Moore or Evorlino but it's there.
http://www.youtube.com/watch?v=eIE5AOayYvI