I have experimented a lot and have definitely found the 1901 rear sight with the peep hole on the raised ladder to give me the best view of the front sight on my M1898 rifle.That has given me the best groupings in my Krag shooting up to 200 yards. It was real hard for me to pick up the thin front sight looking through my Sgt Peep M1902 rear sight as well as the open notch.

I think a lot depends on how good your eyes are overall.