You need to put him in position 9. So he will be the last person to use a mystery. This way you can get the benefit of the 100% chakra.

Team him with anyone who can generate extra chakra and you can get a very strong and demolishing 2nd round. But Itachi is a support he needs to be built around not just added in.

Kankuro 3* (GNW preferred), Tenten GNW both work well with him as they both turn 2 just hit the enemy with the Trifecta of Poison, Ignite and Paralyzed.