I know there's been a lot of talk about eye placement, dominant eyes, etc, when it comes to pocketing balls. How does all of that apply to pivot aimers? Short answer: It's EVERYTHING.
Let's use Ron Vitello's 90/90 system as an example. We all know that the 90-position is exactly 1-tip within the inside edge of the cue ball or object ball (where the edge of your shaft is equal with the inside edge of the cue ball). Some people who learn Ron's 90/90 system call it "life changing" while others scratch their heads because they can't get it to work. It all comes down to perception.
When I first learned the 90/90 system, I wouldn't make all of the shots within the 90/90 range.
Ron Vitello would stand on the other side of the table and say, "Dave, your cue isn't even on the 90/90 alignment line!"
"Bullshit," I would think. "I'm staring straight down the line. What the hell is he talking about?!"
My face was at the inside edge of the cue ball looking straight to the inside edge of the object ball - or so I thought. What I later discovered was that Ron's 90/90 system WAS center-to-edge; it was just a different beginning reference (a different starting point, if you would). Ron also has a different pivot philosophy (hip pivoting all the time versus adjusting the pivot arc with the length of the shot). What this means was there was no way I was sighting the shot from the proper reference point.
Your head/eyes must switch from one side of the center-to-edge line (CTEL) to the other for proper sighting. For all shots that fall within the 90/90 range, your head/eyes must be on the OUTSIDE of the CTEL while determining your cue alignment. The moment the cut angle falls within 90/half or 90/reverse-90, your head/eyes must move to the INSIDE of the CTEL.
This follows basic center-to-edge methodology. All pivot systems with a 1/2 ball pivot such as CTE, Pro1, 90/90--- they're all the same core system. You can't change your perspective and keep everything else the same from one system to the other and expect to make the ball with the same frequency.
Anyways, I thought I'd throw that out there. For those who are knowledgeable with 90/90 and CTE - this might be an "Ah yeah?!" moment. For those who tried 90/90 and got tired of missing the 90/90 shots (the easy shots) and quit--- make this sighting adjustment and re-evaluate.