I find bareshaft testing more suitable to determine spine, then for anything else. The easist, most reliable method of finding centershot, is the "walk back" tune. It usually only takes me a couple minutes to have a bow's centershot using this method. I can get it real close by eye, then a couple shots at 20 yards and a couple shots at 50 yards, and I'll be very, very close. At the most it will take a few more shots to have it exact. When done, test with a broadhead attached, as long as there is no wind.