Wrong drink!(grin) I started with a Coca-Cola bottle then went to the long skinny neck of a 7Up or wine bottle. Then I realized I was unnecessarily complicating my stroke to keep it straight vertically going in and out of that hole. Two vertical bottles to form a gate and a ball behind them a ways for a target was a better method. Three pool balls forming the gate and target works too.
I wasted time and did my stroke harm trying to hold it straight for the length of a coke bottle, the six ounce one. Using a pendulum stroke requires extra wrist or shoulder movement to go in and out of a bottle. I found a channel between two objects to be better. The bottle did cause me to abandon the pendulum stroke so it wasn't all total waste!
I see what you are talking about. Largely removing one variable. Seems the touch of inside would have to be perfectly matched to the spin off of a collision but I guess close enough is good enough to use a different reference point. I stretch and shorten my angles as needed so I guess I have been using TOI, TOO, and most importantly BOC, my personal favorite with TORE being a close second.
Hu