Just use trial and error. I'd go with a 4-3-3 long balls. You have enough quality there to boss about the midfield with Yaya Touré, Gareth Barry, De Jong. Then you have Balotelli, Tevez and Adebayor upfront, which is potentially two target men and a complete striker. You can't go wrong. But then you'll be neglecting your wingers such as Milner, Adam Johnson and David Silva.
City all depends on how you want to play really you got all the players too play in 20 different styles.
Just go for their strengths, the central midfielders and the attackers, so maybe a 4-3-3 with a flat front line is the best, you will probably own ever other team in the league with the beasty midfield and maybe you can even go 4-4-2 with a diamond to fully utilise david silva, or put him as one of the strikers on trequarista.