Caleb mention in a post that someone can estimate the same ball speed for each spin and look at rotor movement patterns. He asks if that was what a person looks for when talking about visual ballistics.
What would be more practical to use? for a signature!
Because I also remember Bebediktus posting a signature where he clocks rotor speed to be same and then looks at ball distances.
Both are in the same range using either rotor or ball distances.
Have someone explore this way.