Ok the f23, 3xxtrait, 3, d2, 3xxEx Breath seems to be the maximum, it does 377,22 on maximum defense characters, I recorded it for the j3 hitting in front. It is 377.22 before the reset and 641.45 after = 1018.67 damage, yooooo
It is tricky, as you can see I use Bizzarro skin and I think the different animation of hitstun on mb breath matters here. But yeah, it is basicly timing. But it isn't necessarily delay. There are parts of the animation where the opponent stumbles back burning, his head moves back and forward, and at different moments your j3 ends up crossing up or not)