Interesting... On CTDS I had the alluring top equipped on Ayla always, because charming is all she's really good for. All the Megaelixers from the creatures in the Giant's Claw really make Lavos and Time Devourer MUCH easier.
The charm rate for me seems to be perfect. I can't think of a SINGLE time in my entire three playthroughs so far where I didn't get something from a charm, even against the Elder Lavos Spawn and Queen Zeal's hands and face. I can't contribute much in terms of probability and statistics, but a good tip for getting pesky charms would be to use Ayla and Marle's double charm.
...is the 9999 damage hit from Robo's Apocalypse Arm considered a Critical Hit...?
Yes. The 9999 damage from the Apocalypse Arm comes from Critical Hits ONLY, so the more often he can do a Critical Hit while using the Apocalypse Arm, the more often you can deal 9999 damage to an enemy. Perfect for winning fights that you need over in a hurry. It's also kickass to see what happens if you take out the last target first in certain fights like Black Tyranno+Azala, Guardian+Bit(x2), Giga Gaia+Arms, Lavos 2+Arms, etc. It sucks the Dragon Tank battle isn't one of them, though.
I remember reading on some guide, something along the lines of
Apocalypse Arm = Instant RAPE, just add Dragon's Tear
