Yeah, I agree. I've noticed that some folks who reach 160wpm+ start to move off from the standard, "best practice" touch typing technique. With the hand guide visualization on https://www.typequicker.com I focused on just following the common "best practice" approach.
I should add a comment somewhere on the site that these are just the general recommended finger placements and not gospel.
Certain keys are just more comfortable with variation. I use an orth keyboard split keybaord as well so for me especially the Z key makes sense to type with pinky. On a standard qwerty keyboard, I've seen folks do both pinky and ring finger.
I don't think either the correct way - whatever variation of standard touch typing feels better and helps you type faster is the solution
After switching to Dvorak, within months, I naturally began touch-typing. I suspect it is due to it being home-row-heavy, with all vowels on the left and most common consonants on the right.
I'm going to be adding additional keyboard layouts to https://www.typequicker.com/practice soon for the keyboard visualization. This might help people who are starting to learn it.
Dvorak seems to be mentioned frequently on this thread alone - I was surprised how many folks use this layout.