Your forgetting that while Sasuke is trying to conjure up Kirin, Naruto is going to notice whats coming and not just stand there. If Naruto is moving fast all around their battlefield theres no way that Sasuke can strike Naruto with Kirin accurately. He could even make himself susceptible to his own technique because while his hand is in the air holding Kirin, the lightning could come down straight onto the conjurer. Because Sasuke could be too busy focusing on where to throw it that he forgets that he has it. Then again I could be wrong, but either way Naruto can dodge it if he is moving around but standing still he wont be fast enough(not that we know.)