I just wanted to clarify that shot arc concept. The smaller the pivot, the less it matters. The DVD is specific to 1/2 tip pivots because very little can go wrong.
CTE as a system doesn't have a pre-configured "offset," if you would. Hal specifically said the offset didn't matter (and he's right); however, additional considerations need to be made if a player chooses to offset beyond 1/2 tip (say, a 1/2 ball).
So, when releasing a DVD and making this as objective as possible without fooling around with a lot of variables - Stan chose 1/2 tip pivots so a player could see results right away.
I know this thread is for DVD-content-only, so I'll be brief. Once your tip offset increases beyond 1/2 tip, the player cannot pivot straight from the bridge as they'd pivot to the incorrect center based on shot distances. That's where pivoting along the OB plane comes in to ensure you're getting to the correct center.
I made a detour this past Sunday to Walnutport, PA to see Hal. I was warned ahead of time that his "clarity" has slipped considerably since my last visit. When I sat by his bed, he was a little foggy. But as soon as I mentioned "the aiming police," "Pat Johnson," "Bob Jewett," and other members of the gang, Hal snapped into ninja mode. In fact, I'm not sure if I ever recall Hal being so cognizant of detail in our discussion! Unreal! Sunny was elated and couldn't believe it. I told her if he ever clouds up, just tell him that Patrick Johnson is knocking CTE on AZBilliards and watch what happens (nothing like poking the tiger through the cage). LOL! (Pat -- hopefully you see the humor in that and don't mind I totally used you to get Hal back into instruction-mode)
One of the questions I snuck in was, "Hal, when you were playing -- what was your bridge length and offset?"
He replied by saying his bridge length was VERY short (about 4-5" or so) and his offset was VERY small (smaller than 1/2 tip). His goal, he explained, was to minimize the chance of "losing the trajectory" to the target after getting to center. The true target, as he explained it, was hitting the exact center of the CB (this lead into a lengthy discussion on how to do that).
Now, I want to preface that comment with the fact that Hal comes from an era where 14.1 was the game of choice. Many of us are rotation players and playing with a bridge that short would break your game. Hal's consideration was minimal CB movement.
In conclusion, smaller offsets mitigate the need to worry about pivot arcs. If you offset 1/2 ball, like me, and pivot from the bridge--- you'll never make a ball. Once you get to 1/2 tip and within, you can. See? Stan eliminated a big variable
Dave