I've seen players changing formation right after match start and i'm afraid of this before championship semi-finals.
Opponent has better players and uses 3n-4-3 formation, so logical choice is 4-1-4-1 or 4-5-1V.
Problem is that his cb-s can play fullback. This allows him to change formation (3cb->lb cb rb) without using substitutions an then will have formation advantage: 3W-4-3 > 4-1-4-1.
So which formation is good aganist both 3n-4-3 and 3w-4-3?
My team is left on this picture.