Okay, how about I post a few images and tell me 
what your expert opinion is?

(Sorry if this seems like a lame excuse to 
display Ifurita cels, but I really am trying to 
learn something here. ~_~)

#4 - This might also be a typical example of a 
grey area for me.  It's fairly non-descript, and 
the only reason why I'm guessing that it's from 
the first OVA is that I'm using the new blue 
versus purple hair test that someone suggested.  
But what are your thoughts on this one?

(This image also came from Yann's Animanga site 
and is for testing purposes only.  However, this 
image represents a few cels I came across and had 
trouble figuring out.  I'm sure that Yann knows 
how to identify his own Ifurita cels, though.)