That would be down to a little trial and error, The possession loss is the games slight penalty for playing a player out of his natural position, but if your expecting to dominate play then it will hardly be noticeable and you will find your out of position player can still put in a good performance, Therefore it maybe worth playing counter formation if your stronger against your opponent but if your weaker than your opponent then its best to put a team out of 11 players that can play well in their positions.