It really didn't work. I tried first putting holes
in the cel bags themselves, but they weren't 
strong enough to handle that without ripping, 
even when reinforced. (Not to mention, you risked 
damage to the sketches if they slid towards the 
part of the bag that had the holes -- and thus 
the rings of the binder exposed to the inside of 
the bag.)

I also looked into hanging tabs to stick to the 
bags (to make them three-ring-binder ready) and I 
did find some for sale online, but they were 
expensive enough that by the time I added in the 
binder and cel bags, the Itoyas would be cheaper, 
believe it or not. o_0  (This is keeping in mind 
that I usually do not put my sketches in bags if 
they're in a cel book, only my cels.)

So in the end, I used Itoyas.

Many Sharp Smiles,
--Drac