what are the best formations that you can easily switch from defense to attack?

[nikolgiorgos]

And you can transform it to some different formation if you have multiple position players.

Exactly. This is the key to make transformation.
This is my new team.
The first group are the new fast trainers. I gave them some extra positions.
The second are just simple players from the market.
The third group are low q players (0t academy), to keep low my q avg
With 15 players i can do rotation or to change formation during the game.