If the arrow's dynamic spine is correct, your arrows will be "on" at all distances (not just up close), and the 'average group center' of several groups should show a matching point of impact.
My hunting is at very close range, but I like to do my final bare shaft tuning at 40 meters (about 44 yards). When I get the tuning as close as I can at that distance, I cross check with fletched shafts w/broadheads vs: bare shafts w/field points.
When I feel I've got everything as perfect as I can with the arrow's dynamic spine, I then check to see at how close a range I have perfectly straight arrow impact; with both the fletched/broadheads and bare shaft/field points, into a uniform density foam target. That's generally around one yard (from arrow tip to target). Then I do a few random checks at various 'in between' ranges.
Hope that helps a bit,
Ed
TGMM Family of the Bow