That's awesome.
I don't plan shit all, I don't play enough to notice a pixel in hitbox width difference in SA, and I certainly don't care if it did exist. I did know that Marisa has a slightly larger horizontal graze distance, but I didn't care since no, it doesn't affect my gameplay. I still rush into lunatic guns blazing. True, I probably won't get decent 1cc lunatic runs, but I have beaten IN lunatic several times with all the characters, and I still don't notice this hitbox shit (that is, until theshim mentioned that nifty Xu Fu hitbox trick, pretty convincing).
Like really. I have maybe 80 tries on my highest tried card on IN, that were mine anyway. I don't play that much. Ahh wait, I have 150 on Unseasonable Butterfly Storm because I fuckin' love it, and 140 on Flawless Nirvana because it's pretty beast too.
And I do have business playing on lunatic, because even with me not giving a rat's ass about minute hitbox size variations, I can still beat it. It matters to you, who is much more of a perfectionist than me, but no sir, it probably does not matter to lunatic runners in general.
Maybe Cave Ultra mode runners, but let's not go there.