Bare shaft into a soft foam bale will tell you what your arrow is doing in flight (as long as you can see it) and how it's impacting. Ideally you want it flying straight and level--no fishtailing (side to side movement) or porpoising (up and down movement). You can also shoot through paper--you want a bullet hole, but a slightly weak and slightly nock high showing is generally acceptable. No idea if the two different shafts will be the same spine.

Chad