Because OEM hands down is the best thing for hondas unless you're doing an after market product like MSD. I've used a lot of different cap/rotor combos due to having like 4 shit alts that would eat them up.
dremel a slot FTW I've done that many times. When you put new screws back in, use the kind that have the 10mm heads. so you can use a wrench next time.
I believe OEM honda stuff has the 10mm heads (again FTW). Is your cap an after market piece?
10mm bolt FTW!