I don't scratch very often. I learned long ago that being scared of scratching magically guides the CB into a pocket. Thanks subconscious, not quite what I meant but you see in visualizations and I visualized it into being!
For me, it's not an anxiety reducing thing. For a good stroke, I know how the cue feels for me personally. The other fingers are duds, the ring is the sweet spot.
I understand what you mean about the mental aspect of it, but the same could be said for almost every aspect of a PSR. For me, my stance/my stroke/etc, I find that the ring finger is dead nuts feeling when I stroke it good. To the point I make sure the cue feels right based on that finger. It's not a mental thing for me, it's part of a checklist that tells me everything is in order. I like feel more than thinking. Thinking can get you if you're not careful to shut it off at the right time.
Try this. While standing hold your arm at your side. Curl your first finger tightly. Quickly raise your hand as if you're trying to poke your shoulder with your thumb. Try pivoting your wrist while doing so. It's just a little experiment so try different motions. It's similar to an underhand throw. Pay particular attention to the stresses on the muscles and tendons in your wrist/forearm/bicep/etc. Which one allows the smoothest motion? One feels way less stressful on the wrist/forearm for me. It's the ring finger, the pinky feels second least stress on the wrist/forearm. The middle finger feels very stressful (on the ligaments) as does the index. Different digits cause more or less tension in your arm and stroke. The ring finger also lets me freely pivot the wrist in a straight motion without additional stresses to overcome. It feels the smoothest for me.
Experiment when cuing sometime during practice. One finger will feel best and result in the smoothest stroke. Some people may use more fingers, different strokes, etc. For a pop stroke player this will probably not help in the slightest. For a smooth stroker it may.
It may be different for everyone on earth, I don't know. I do know that the ring finger works for me. It allows me to smoothly stroke and keeps unwanted tension out of my stroke. It allows me to stroke a ball and get action without killing the ball or stroking harder than needed. It's not magic but I about shit when I tried it. I've been doing it for several months now and I'll not change it. It shows me through feel that my backhand is properly addressing the cue.
Some people hold the balance point of their cue when up and walking around. Why do they do that? They are gathering information about how to hold the cue, even if it's subconscious. People are strange and most of this stuff is best not to over analyze but it's part of the game.