I think the problem with chines fonts is, that the letters got bigger boxes than the western ones. In normal it doenst matter to the font, if the size of the box is bigger than another but on the very small screnn of an e-Reader it seems to be important.
If i am right, you need some fonts, that contains the blocksize of the letters.
Perhaps the GfK could patch this out, that they read the size of the block out of the font-file.
What kind of font are you using ?