I've been spending more time in the last 6 months actively playing with my PSR than probably any other time in my 20 years of playing. After getting back into it again, watching a lot of matches, and seeing my own inconsistencies, I decided to focus on it more intently.
Agree with Scott Lee and others, it's important to have a good routine for consistency, pressure proofing your game, etc. Whether you actively work at it or it comes naturally, most of the top pool players, golfers, free throw shooters, etc. have one. Studies have shown that a top player will use the same routine and number of strokes on the majority of their shots, only varying (sometimes) on easy or difficult shots or certain specialty shots. What's important is that it fits your natural rhythm and eye movements and becomes very natural and something you can fall back on.
For myself, since I wasn't getting some answers I was looking for and was still questioning my own rhythm, I actually came up with a chart of various combinations - starting with a pause or stroking as I'm getting down on the shot, taking various numbers of strokes of different lengths, etc. I ended up with 10 or 12 combinations that I thought were reasonable for me and played 5 - 10 minutes with each one night, keeping track of what I liked and didn't like. I was able to quickly narrow it down to 2 or 3 routines, the others just didn't feel right. Then I played with those some more and landed on a combination that I liked. It was nice, once I did that and could stop thinking about everything else I improved my consistency and overall game. I'm also more aware of when I'm not in my rhythm, enabling me to switch things up mid-match and get back in stroke.
Hope this answers your original questions, even if a little out of order…
Scott