How To Grade Porcelain Coins?

There aren't really enough porcelain coins around to develop a separate system of grading for them, yet at the same time the conventional coin grading system based on metal wear is inappropriate. I would think that porcelain coins should be "graded" in much the same fashion as any other piece of collectable porcelain, like a china cup, doll, salt-shaker or other knick-knack.

A "Collectables" forum (I believe that's spelled "collectibles" in America) would probably be a better place to find answers to this, but I imagine that the important criteria besides "wear" are: damage (in terms of chips, breaks and crazing), colour, staining and originality (in terms of attempts at repairing damage).

Judging by this guide on valuing a porcelain doll, they seem to have much the same scale we use for coins - and given the common usage of the phrase "mint condition" to describe things that are "New" or "As New", I would assume their terminology was actually copied from coin collectors.