Actually his strongest Suiton is Giant Vortex Jutsu, which requires 18 seals.
Btw saying how he has to use 42 seals to perform Water Dragon Jutsu, implying he won't have time is a pathetic argument. Sasuke noted how Zabuza performed so many seals in seconds. Zabuza has a 4/5 for hand seals according to the data books; that's the second highest of the entire akatsuki, right behind Itachi. He can perform seals so fast that he blitzed Kakashi with Water Prison Jutsu which needs 8 seals. Not only that but Zabuza also has all the time he needs in the mist to perform seals and he cal also use Water Clines to stall so that argument isvweak,
OP: I think Chouji solos, which I honestly can't believe. Actually, if Chouji is exPpands his body with chakra, if Zabuza and Haku ambush him with melee weapons and large scale Suitons, couldn't that potentially disrupt choujis chakra flow and revert him back to normal siza? That expansion technique can't be that powerful, it has to have weaknesses, it's not even a famous technique. Also remember Chouji and the others can't find zabuza in the mist so they basically can't hit him
Actually I think Zabuza and Haku may take this