It is difficult for me to entirely understand the relationship between the various U. S. Krag rear sight models and the front-sight blade heights usually 'matched' with them.

When a Krag Rifle or Carbine was accepted into service or left Springfield Armory, there must have been a well thought out and tested rationale.

Also, most Krag sights were designed around a loading with a 220 grain, flat-based RN projectile, moving at 2,000 fps muzzle velocity.
(Exceptions would be, the 1898 ammo with a 220 grain bullet moving at 2,200 fps and Frankford Arsenal 1907 'Palma Match' ammo with a 203 grain 'pointed' projectile).

I do not know if different height blades were ever used with these 'exceptional loadings'.

Of course, there is never a complete guarantee that a Krag's sight parts have not been switched at some point of time (and by whom).

Out of curiosity, I measured the height of the bottom of the "V" Notch, above the top of the barrel radius, of various Krag rear-sights, that I have available. The rear-sight blades were at their lowest setting.

It was difficult to get consistent measurements. (Note - The U. S. Ordnance Dept., likely, would have based such measurements from the 'axis of the bore').

FWIW:
1892 Rifle rear-sight "V" - .477" above barrel radius (FS blade .275")

1896 Rifle rear-sight "V" - .468" above barrel radius (FS blade .286")

1898 Rifle rear-sight "V" - .440" above barrel radius (FS blade .413")

1901 Rifle rear-sight "V" - .493" above barrel radius (FS blade .413")(not in picture)

1902 Rifle rear-sight "V" - .425" above barrel radius (FS blade .413")