When I was a young lad I attended biathlon training back in the old country.
And these links are very similar to the training I received. The mental ability to trust your repetitive tasks are key to performance. Now each tasks have to be drilled over and over and then put together, if you do not, you lose track of what changes made what difference and progress halts, but even worse the mistakes changes which leads to frustration, perhaps blaming equipment, ammo, or other things.
We always trained on specific metrics that was tactile, grip pressure for instance, we would send 100s of shots down range just feeling what your optimal grip pressure is (it varies from person to person) After a while you get a feel for it, and if a trigger pull is too heavy/light you either adjust trigger (prefered), or adjust total grip force to compensate if the trigger isnt adjustable.
Trigger finger position: as you know, some people have long fingers, short, thick, thin, etc. So it's important to find where the optimal roll angle (without strain) of the wrist is, to ensure perpendicular trigger finger pull.
Anyway it was cool to refresh some information from a time long ago:-) thanks!