Multiple Player Info?

So I want to play the SP stuff as "Player X" and son wants to play as "Player Y", I tried doing a dual install -one install to drive 'C' and copied to drive 'E', but all the save game info is in one place 'docum.... blah\blah\settings' folder.  So I guess the only way is to just stay with the single install and whenever I play change the name to "Player X" and when he plays changes the name to "Player Y"??

Just want some clarity on this.