First bit is a 'no brainer' IME, which is the reason I so strongly disagree with your presumption that long toes on TWH's for eg is OK - biomechanics aren't breed-specific. Every breed is structurally the same.
Not sure I understand the second part of what you said above, in relation to the first. IME toe length doesn't govern whether a horse has a heel first landing ...Except maybe if toe is so stretched & sensitive as to force a horse onto his heels.
The TW babies I worked with had a natural 3-beat walk.
Have you ever seen a quarter horse do a 3-takt?
Shoeing the lite shod Tennesse Walker 3:30-
Did you not understand the other film......conformaiton and the slope of the shoulder.
The best I could find, what did you not understand?
Normaly the heels take a lot of wear and punishment as it is so why would anyone want too over work them even more with heel landing first?