New update: I'll try to keep this short but I'm sure I'll fail miserably.
TLDR: OP may have found his holy grail of repeatable, unconscious performance using relaxation and rhythm and timing. OP needs to figure out how to maintain this throughout all racks in a match.
In the last couple of weeks or so I have discovered something about my ability to execute. It's subtle but it has made an incredible difference in my accuracy.
In line with what many of the posts in this thread have emphasized, conscious v unconscious execution is indeed a thing. Here's what I've discovered about my particular ability to "summon" my best game:
Stand behind the shot, face square and plan the speed and CB address point for sinking the OB and getting shape.
Step into the shot, without obsessing about foot placement; just let it happen. *
Confirm cue alignment (call it "aim"?) This can take me 3-5 seconds, eyes between CB and OB a few times. Settle eyes on CB tip contact point. While doing this, perform one or two (usually one) full-length practice strokes, using the stroke length required for the speed of the shot.
Raise eyes to OB. This is the important part: Brief pause, maybe about a second. Don't think. Feather twice, about 1" strokes. Backstroke, barely imperceptible pause at the backstroke, shoot. **
* While I try to avoid inconsistencies. I've noticed that I can sometimes be a little off with foot placement, yet still make the shot. As long as it feels about right, it's OK. I think it's more about allowing the subconscious adjust as long as I don't think about it.
** If for any reason I don't have the discipline to follow "Feather, feather, backstroke, short pause, shoot" and think
about "feather, feather, backstroke, pause, shoot", where maybe the feathers are 2" instead of 1", or the pause is 1 second instead of an unthinking sub-second pause, the chances of me missing are MUCH higher. I've also noticed that this "feather, feather, backstroke, short pause, shoot" has a definite rhythm and cadence. If it's a certain cadence, I'm gold. If for any reason I deviate, results are inconsistent.
I've also noticed that doing this allows me to trust the shot, and I tend to refrain from squeezing the cue. What I am describing sounds a lot like I am over-analyzing this, and that I am making this process robotic, but when I apply the cadence naturally, it's very much NOT robotic. It's hard to describe, but there's a certain "it" feeling when I'm doing it right, and this allows me to do it right more often.
Last night I applied this during league. I performed well above average (APA SL 5/5). I even was able to run out a 9-ball rack from the 2-ball. and after being given a rack where my opponent ran to the 8-ball and gave me the table back, ran out that 8-ball rack.
I *think* this is what posters here have been trying to convey. Find a PSR, rhythm and cadence that works for you, remove the brain from the process, and let it happen. At least I hope so.
My homework, now, is to maintain this throughout a match. I need to figure out why, but my performance in a match is usually much better the first few racks, then starts to fall off. I think I get caught up in the match, and my relaxed state of mind diminishes, and I probably start thinking about things again without realizing it, and tighten up. Last night I had to grind out a 9-ball win 38-31 in a 38-46 race after leading 10-0 and 18-1 after two racks. Also, in 8-ball, I was up 2-0 in a 4-4 race, and ended up losing hill-hill 4-3. I think, though, that perpetuating my "formula" as described above will allow me to perform well throughout a match, not just in the first few racks.
As always, comments on my journey welcome.