Easy Arrows will auto-orient built-in arrows, or custom graphics & compositions, to your Shape Layer path. You have complete control over the styling of the path & the attached objects, even after the script has been run.

With Easy Arrows, you can:
    Use built-in arrows or custom graphics & compositions.
    Easily update your path after running the script.
    Control the styling of the stroke, however you like.
    Quickly change color & size of the entire setup.
    Precomp for easy duplication.

Home Page - http://aescripts.com/easy-arrows/