As far as arm bar, I think it can hinder a swing when not adjustable. Keeping your hands close to your body w elbow flexion is what I prefer at set up. I think it helps movement w the body and intent with the hands during the load. Extend as needed for timing and or location. Craig Wallenbrock says maintain the ‘box’ at set up for as long as possible.
But like anything in hitting there are outliers.
But like anything in hitting there are outliers.