This is an old thread, but since it just came back to life:
Breeding a cinnamon male to a whiteface female (pair #1) will give you this result in the first generation: all sons will be grey split to cinnamon and whiteface and all daughters will be cinnamon split to whiteface.
Breeding a whiteface male to a cinnamon female (pair #2) will give you this result in the first generation: all sons will be grey split to cinnamon and whiteface and all daughters will be grey split to whiteface.
Breeding the children of pair #1 to the children of pair #2 will give you some visual cinnamon whiteface in the second generation.
The cinnamon mutation is the same gene in both cockatiels and budgies, and the lutino gene is also the same gene in both species. Whiteface is the same as the blue gene.
Cinnamon and lutino are NOT co-dominant, since they are completely different genes and co-dominance is something that occurs with different variations of the same gene. But cinnamon and lutino do interact with each other somewhat, because the way that cinnamon interferes with melanin production has an influence on what the lutino mutation does. I have more info here in my coloration mechanics article: http://www.littlefeatheredbuddies.co...cinnamonlutino