LOL - you guys are killing me with all this "Old way doesn't work anymore". We can agree to disagree.
The wheel is not for the shooter, the wheel is a memory aid for the coach. The shooter should never be allowed to see it.

It is also not all inclusive - for example: A right-handed shooter in a combat stance will shoot low left when he closes his off eye. But not every time. And not much. And only if he has his off foot forward.
TS and TR are right of course. The biggest mistakes most people make are going too fast and/or learning the skill poorly. Imperfect practice is worse than useless.
You posted while I was writing. I agree 100% about the being tired. I also agree most don't see it or recognize it as a factor. Excellent post.