I guess if you have 2 players for example one who is DC and other is DC/DL then choosing who plays in DC wont only depend on where he performs best but also on your opponent attckers/wingers or whatever

if the opponent uses a strong ST then I need a more defensive player with a defensive attributes then I will select the one who does this for me

it depends on every match and what qualityyour opponent or what you want from the match