Right the safe normal option would be to put blue or no arrows on the defenders, no arrows or red on the DMC!, reds on the all midfielders and strikers! thats what I would do!. as for settings try this for starters then tweek to suit different opposition.

Team mentality... Normal or defensive for playing against stronger teams and attacking for weaker teams.
Focused passing ...Mixed.
Pressing style..Own half.
Tackling...Hard for stronger teams .. normal or hard for weaker teams.
Passing style.. mixed
Marking style ..Zonal.