What formation should I use with these soccer players for a fifa tournament?

4-2-3-1. Lucio and Cetin together on CB. Riise LB, and Zuniga LB. I think Cahill is a defensive midfield. Then have xabi and Cahill playing as the 2 defensive midfields. Valencia as a RAM, Guti CAM, assuncao LAM. Bojan as your striker.