"Gameplan" vs. "Playbook" screens for CPU coaches

[john_connerson]

I'm basically playing as a GM with my coaches and coordinators controlling the on-field action. Do I want the gameplanning coach to have a higher Preparation rating or Coach Offense/Defense rating? What about my playcallers? Does the Flexibility rating mean my playcallers work better with a different gameplan, or vice versa? Or does it go both ways?

Also, do the coaches automatically set the depth chart based on the gameplan or can I set that myself?