Why bomb more when you can one-death the entire stage using somebody with...
Better Bombs (ReimuB, Marisas, SakuyaB - for the spellcards)
Better Shot (ReimuB, Sakuya B, Marisas)
A shotgun with worthwhile damage (Reimu b, possibly MarisaA)
A spread with actual damage (ReimuB)
A focus bomb that doesn't leave 500 bullets on screen after it's over (everybody but ReimuB, possibly)
The ability to kill stage enemies before they kill you (Marisa has movement speed, Reimu has spread and homing, SakuyaB is fine)
You shouldn't need to bomb 28 times to make a shottype worthwhile. Plus, it's not DURR HURR WHY CAN'T I 1CC PCB NORMAL.
I'm seriously going to skip Sakuya A and move to Marisa B for now while I'm trying to clear Extra with everybody. At least Marisa B is the second strongest at long range.
Actually, I should probably stop trying to stay under a boss so much, since she gets crappy damage no matter where you are.