Well, as long as your cels fit in, anything's 
fine. I don't really know what devices you're 
talking about, but I made good experiences 
with "Simple is best". Which means I reserved a 
drawer for my cels and threw them all in there. 
It's good to keep them in celbags, or Deleter 
bags so their paint won't stick the cels 
together. Plus, cels should be seperated from 
their sketches every now and then as they tend 
to stick together after a while. 
But really, all the special cel storage 
inventions they throw on the market, are 
bulldung to suck your money from your veins. 
Another nice thing are the plastic file cases 
they sell in Japan. Order from Celga and the 
chances you get one are 99% ;) They easily break 
but they're nice for storage and transport. 

To sum it up, just keep your cels bagged (I 
repeat - deleter.com), and toss'em in a dark 
drawer or cupboard. 

Cels aren't all that sensitive as some ppl say. 
Like don't touch, don't bend... the truth is 
that cels can take way more than your usual 
drawing. As long as you don't crease, scratch or 
overheat them...

Personally, I prefer to store my cels on the 
wall ;)

^^
Anna