It depends on what type of front sight one uses. I can tell you my .040" wide post in my globe sight is equal width to the size of the target at our 1000 yd. range, and that target is 36" round. So when I'm sighting with a post insert I sit the round target on top of my front post and even up the edges side to side.
When I'm shooting at closer 400,500 and 650 yds. I choose a front aperture insert that allows me to center the target regardless of size in the middle with as little light around the target as possible. The larger that aperture is, the more it allows me to be off perfect center, and group size opens up slightly.
Of course with scopes on my old single shots I simply center the crosshairs regardless of distance.