If you own an O'Hare micrometer for the M1905 rear sight of the M1903 rifle (0r the Ray-Vin recent reproduction), you can use that to set the elevation on the M1901 Krag sight precisely and repeatably.   Windage is another matter.  There is a friction clamp on the front of the M1901 sight ... you move the lever to release the lock, and then you must push the sight with your fingers, and relock the with the lever.  There are marks (called "points") on the sight base for reference, and each of these "points" is equal to six minutes of angle: 6 " at 100 yards, 12" at 200 yards, &tc.   Needless to say, this method is neither precise, nor very repeatable, but it is simple.  You do have the choice between a "notch sight" with the ladder down for less than 400 yards, or the tiny peep with the ladder up.

I have run over the alloted characters, so will have to split this post.  Stay tuned ......

Resp'y,
Bob S.