Snooker fundamentals can affect what some would consider "preferential" break shots
Steve:
As you noticed during the 14.1 Challenge at SBE, I am a right-handed player with snooker fundamentals, and I prefer what are normally considered "left-handed-player break shots" (i.e. cutting the ball to the right). In your WEI table diagram, of the two possible corner-pocket break shots you show, I prefer the 3-ball over the 7-ball.
(By way of comparison, I don't have a preference for either of the side pocket break shots -- either one is fine with me. I'll explain why there's no difference with the side pocket break shots in a bit.)
The reason I personally prefer "lefty" corner pocket break shots is because of my snooker fundamentals. I like to position myself square-shouldered to the shot, with as many of my body's joints facing INTO the shot (e.g. hips, knees, feet) as possible, with my cueing action as close to my body as possible (using the school-taught
4-point contact) as is standard with snooker fundamentals. I can do this with "lefty" corner pocket break shots, even if I have to use the bridge/rest. If I have to lean over the table from the table's left side to shoot a normal "right-hander's" corner pocket break shot (i.e. the 7-ball in your diagram), I have to shoot "across" my body with my pendulum stroke away from my body, and I don't have the precision stroke as I do when getting behind the shot square-shouldered. If my only option is to shoot a right-hander's corner pocket break shot, you'll often see me considering the use of the bridge/rest to shoot that shot (so that I can get fully "behind" it, square-shouldered) even though I can otherwise easily reach it by simply leaning over the table and shooting sideways, across my body.
Now this doesn't apply to side pocket break shots, because I can always reach these with a square-shouldered stance.
One of the reasons why the square-shouldered snooker stance works so well for me, is that I'm one of those rare breeds who has true binocular vision (as diagnosed by an optometrist). Although in my 40s I am starting to suffer "
cholesterol floaters" on my eyes, virtually all my life I had no real dominant eye. I can shoot a rifle just as well with either hand/eye (and skeet shoot with a shotgun with either eye, although I can't pump the shotgun as fast with my right hand as I can with the left). When I hit my 40s, I noticed I'm starting to suffer more cholesterol floaters in my right eye, and I now find myself favoring my left eye when reading fine print. It doesn't [yet] seem to affect my preference for placing the cue smack-dab in the middle of my chin, with my face as square to the cue (not slightly turned to favor one eye), though.
Anyway, I hope this helps explain one angle of why "lefty" vs. "righty" corner pocket break shots. I know it's probably an unusual case that probably doesn't apply to the majority of people who play straight pool.
-Sean