My Yamato deals 45-50K non crit per auto. That extra 10% does not equate to 5K increased damage unfortunately. Maybe if the barrier attack is included. I'll have to test but doing quick math in my head my Iruka's auto is 12-15K plus guaranteed crit on chase and then WB Asuma hitting for similar damage. I think that because of Iruka's chase I might pull slightly ahead with Pose of Duel or if it's weaker it might be barely weaker. I'll test on the next Nine Tails. My normal damage per fight is 870K so if it's anywhere near that or above I'll let you know!
Yes the barrier attack would be included since it scales of Yamatos stats, but also don't forget main and Tonton they do decent damage too.