Thanks Paul for adding experiences.
 
I've only seen one true cinn.  Since he's passed on, I cannot confirm it,
but I think if you microscopically compare a dilute choc hair and a cinn
hair, observing the root/shaft/tip differences, you may see a white tip on
the choc.  and the cinn should be even in all three zones.
 
If you hold an actual stick of cinnamon spice next to a chocolate or
champagne ferret, the difference will be in the hue, the lack of ruddy
redish brown, and the spice will almost match a cinnamon ferret.  Truly a
beautiful animal, but then, they all are, aren't they?
 
You've included some references, and I'm using what I think used to be my
memory... which I would like to refresh, now that the subject has arisen..:)
 
Bob
[Posted in FML issue 1906]