Breathiness is one of those parameters best used in moderation, I think; when used excessively, it just sounds... wrong. (Rin especially has an odd reaction to it, especially her Power bank. At least that's what I've noticed.) Just mess around with breathiness and maybe clearness as well! XSY might also help you out. Her V4X Sweet bank reacts best to breathiness out of all of her banks, as it's already fairly breathy. Best of luck!