It's difficult to respect a position that goes contrary to the recollections of many who saw him in person multiple times and the available video record.
Lou, I understand you. And I thank you for the restraint, because I know my (and others') viewpoint on this bugs you.
But even Bob has (or had?) the viewpoint that Mosconi had a slip stroke:
http://sfbilliards.com/articles/2005-10.pdf
Do you want to play like Willie Mosconi? Then you have to use the slip stroke, because he did. As shown in Diagram 1, during the backstroke, the hand slips back on the cue stick, then it grips the stick and the stick is brought forward as usual.
I did see Willie perform an exhibition in the area where I was growing up in the 1970s, although I was too young -- in age, as well as my pool knowledge -- to even notice, or know what to look for in his mechanics. All I know is I saw a 100-ball run, on command. I wish I knew then what I know now.
But, in several videos of Willie, I see this very slip-and-regrip action. He doesn't use it all the time, of course. He seems to use it on power strokes -- especially break shots.
The below is an example (with time hack):
http://youtube.com/watch?v=1ts7YqHRrjc#t=6m20s
Notice on the pull back, the hand slipped backwards, regrips, and delivers the cue. (Willie also integrates a wrist-flop in there on this particular shot, but that is inconsequential to what we're talking about.)
He does the slip again in the very next shot:
http://www.youtube.com/watch?v=1ts7YqHRrjc#t=6m30s
Mind you, the slip is only a couple of inches -- a modest slip, but it's still there.
And yes I have said before how it was amazing to watch his CB plow repeatedly into the rack as if there were a little engine inside the ball. And lastly, the CB does not care where your grip hand is or what it's doing, slip stroke or no.
Lou Figueroa
Never said the cue ball "cares" where you grip the cue. Only the person delivering the cue, does. Forward force is forward force, no matter how it's applied behind the tip of the cue. And also I didn't say the power stroke in question "requires" a slip stroke. Only that a slip stroke seems to enhance it, or that a person who uses a slip stroke seems to really let the slip stroke out on this type of shot.
Obviously, a standard grip/stroke can also impart the same kind of power on the ball. I just found that, in my slip stroke days, I didn't have to put as much "oomph" to get the same amount of power.
And also, I agree with Bob that you want medium power on most break shots with top applied to the cue ball -- otherwise, the cue ball climbs up and over the rack like a monster truck.
-Sean