Spell Interruption Rate Down - Capped?

[Shinhiryu_Kage]

So, I know that SIRD (awful acronym lol) works for Ninjutsu.

But I'm curious if anyone has read or heard of how much? And exactly how does it apply? Big question though was, does it cap?

I think I vaguely remember that.... it works where it stretches out the time on the casting bar between 20% and 80%, expanding that range and just by a percentage of some kind?

I don't know the gory details, but I really would like to know. I remember when I was like in the 30's on NIN, (actually replaying it again on my new char) where I got Nikkaroe and some other SIRD equipment and I noticed a big difference in my casting interruptions.

Anyway, could anyone enlighten me?

[Reyes]

I don't think there would be a cap at all, if any. There isn't much, eh, "SIRD" equipment that would be very viable for any class, unless it has extra stats on it.

[Arosan]

i believe hearing it caps at 50%, but not 100% sure

[Armando]

I've heard it's capped at 50% and that Aquaveil is supposedly 25%. I suppose it wouldn't be hard to test with double Hermit's Wands, Aquaveil and a Heko Obi +1.

It doesn't do anything for the range of time during which a spell can/can't be interrupted (though I'm somewhat doubting if such a range even exists? Hits not interrupting the a spell just as it starts might be due to lag.)