4 4 2 narrow diamond

hey, i'm playing against my friend away (he is 1st on the table and i'm 2nd) and he's using 4 4 2 narrow diamond. my quality is better by 5 than him and last time i played against him away, i used also 4 4 2 narrow diamond cause i have better players and i man marked him. i won 2 0. well, my question is, is it better to play the same formation that he plays or is it better to counter that formation ? is it better to play with your "strongest" formation (with the best players you have) or to counter his formation ? thanks.