Thanks you all for your help. Now I have to take a decision.
I ask you guys, what formation do you prefer ?

butterfly ?
3W-2N-2N-2W-1 ?
3W-1-4-2 ?
4-1-2N-2W-1 ?
3N-4DMs-2N-1 ?
5-2MCs-3 ?

It's time to vote !