Your M1 has the easiest time of being in the vicinity of the target on the first shot than all of theirs. The math is already done and calibrated onto the rear sight. Use similar to as-issued ammo, and dial it to the 10 on the sight. With match ammo, you'll find it closer to 800-900 on the setting. In any case, you should have a normal sight picture with your target above the post.
For the M1903A3, when I shoot at the big 960-yd plate on one of our local ranges, I put the sight on 650 and then ignore the front sight blade, and just use the front sight base as the front sight itself. Same at the 1100-yd target. I use the max'd out setting of 800 and the front sight base instead of blade.
Now, wind is another story.