Jakes,

I hate to break it to you but you are incorrect. You can predict which arrow is going to fly out of your bow if you know what deflection/spine weight tunesout of your bow.

Feathers and steel behave differently but one pound of feathers equals one pound of steel.

An arrow regardless of material that deflects the proper amount will go through the parodoxial nodes of bending and clear the bow. The same will be true for any arrow material with the same amount of deflection.

You are correct that there are several variables that go into selecting an arrow shaft that will tune properly. That is the reason an answer such as "it works for me, it will work for you" does nothing but mislead.