Conte even said himself that he plays a formation that suits the players at his disposal. Like a suit he tailors to fit the players. So you are right, I can't see him playing a 3-5-2 formation with the defenders at his disposal currebtly but that could change once Zuma is back. Also if Alonso proves to be an asset in an attacking sense, hemight try a Zuma, Luiz, Cahill trio with Azpi and Alonso as wing backs. That would be in specific games in my opinion not just a set formation for every game.