It's a bit late, but hitbox size is a huge difference when you're the crazy nut whose strategies always involve high-risk dodging. >_> Also, play MoF extra with Marisa and then with Reimu and tell me that hitbox size doesn't make a difference.
ANYWAY! I don't know if this is in the spirit of this thread, but I've figured out some strategies with two of Byakuren's spell cards others might find interesting:
Magic Milky Way: Start close to Byakuren, dodging the curvy lasers by moving up. Once she starts shooting the stars, swerve around them a couple times, then start moving down as the lasers allow. Repeat until you reach the bottom. This minimalizes the amount of time you're spent at the mercy of the bottom of the screen.
LFO: I'm sure Baity's going to laugh at me, but I realized that you can misdirect the waves by flying off at an angle not center. The waves are centered to be thickest at wherever you are when they fire, so this usually decreases the amount of bullets you have to squeeze through. All my dodges I've made until now have been hitbox prayer dodges, but by flying off in random directions before a wave is fired I captured LFO without dodging a single hard wave.
Also, while I can't really help with St. Nikou's Air Scroll (it's completely different on lunatic and possibly easier), I find it amusing that it takes the same amount of time to kill Byakuren at 1.00 power as it takes to kill her at 4.00 power on Superhuman.