12 to 25x will give you very precise aiming holds if you have a fine reticle or, better yet, a floating dot reticle. With a fine reticle, I get by with 12x for the task you describe. Another possible help... shoot at a target with vertical and horizontal stadia line extending out from your X ring. When the lines are covered by the reticle, you are pretty well centered up- even with a 7x.