Whatever works for you, I guess. Or for svb.
And I'm not theorizing about others. I've had this discussion at various tournaments (and not started bby me either) and I've a pretty good idea what true players do and don't do. I'm talking about most of the older players who are now long dead. I've played quite a few of those who were in Varner's generation also. But that was a long time ago before systems became the fashion.
I'm curious when you say you look at the edge. Do you see a disc, or just one edge?
Mind you, I've been accused of being over analytical as well. But that was quite a few years ago.
Ultimately that is ALL it comes down to. Dave Segal, a big aiming system proponent on this site, has said repeatedly that pool is really easy to keep score in by looking at whether the ball went in or not. Billy Incardona said he prefers to play for money because that's real easy to keep score on, are you ahead or not.
So for all the put downs and crap people sling here it all comes down to each person knowing for themselves if what they are doing is working for them. I know it by using Dave and Billy's methods of keeping score.
I really don't want to get into how I aim here. This thread was somewhat maliciously started by someone who just wanted to put down those of us who like to mess around with aiming systems. I stated that when I learned to aim using systems my cue ball control got way better.
But the guy who started the thread didn't want to hear that. He was only interested in putting down anyone who doesn't subscribe 100% and only to the hit a million balls method of getting better.
I too have been to events where some of us talk about methods and techniques. No one gets hot and calls the other guys suckers. It's all friendly sharing of knowledge and ideas.
People naturally look for all the ways possible to do things. That's where progress in all fields comes from. There is almost never only one way to do something. Especially something so invisible as a human being aiming one object at another object. We use whatever we need to help us get there, be it imaginary balls, imaginary grey gutters, light reflections, shadows, portions of overlap, ferrules, centers and edges of the balls, whatever, all of it is in service of finding a place to stand and bend down and shoot the ball.
Its the same for pros as it is for amateurs. Only the pros have mostly settled on something that they trust and have moved on to working on their mental toughness under pressure.