You should finish that combo with 623B since it works on more characters and also gives you better oki (wut)
And the combo is easier if you do a 6D instead of a 66.
I personally use the alt.623 Sliding Ascension Kick, so C's the blatant choice for me. :V You have a point though, I'll keep that in mind.
While we're talking Reimu; Spread Amulet, or Youkai Buster? Buster seems really weak as of 1.10 (though the resulting knockback on block is sexy), while Spread's damage:proration ratio is really nice, and can be used for staggered hits when comboing into spellcards. Though, it lacks the usefulness in air-to-air combos that Buster has.
EDIT: Woah, I found a little graphical secret with Fantasy Heaven. I haven't confirmed it as the cause, but if you light the last orb when inflicting +100% limit, you'll get this giant fancy spell circle:
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