BTW the formation is 1-4-3-2-1. The first is the one who decides then game, yet everyone forgets him.
Coming back, 4-3-2-1 is what Barça tends to play, evolving from 4-3-3, with MSN in the front. Keeping mind tiki taka, passing mixed and short, attacking and high press would be dangerous. Red arrows on fullback has been de facto on any formation. I will try it out next season.