True, Porcelains are lavender diluted Mille Fleurs, so they have 2 copies of the mottling gene, the Self blue wont have the mottling gene. And like mottling, the lavender (self blue) color is also recessive and since both of the parents already have two copies, all the chicks will as well and they willl be lavender, but they will only carry one copy of the mottleing gene so while they may have light mottling in their juvenile plumage, it will molt out within a few months. If you breed those chicks back to the Porcelains, then you will get about 50% of the chicks that will be mottled like the porcelains, but it may take another generation or two of breeding back to get the gold color back like it should be again.
Thanks so much for the information. I have a porcelain roo I like, but am having no luck finding any porcelain hens. I am gonna put him with a self blue hen and a mille fleur hen for now, and see what I can do....thanks again
Oh Well the Mille Fleur hen with the Porcelain roo would be your best bet, breed the Porc. roo to the MF hen and that will give you all Mille Fleur chicks that are split lavender, breed them back to the Porc roo and you will get half Porcelains and have Mille Fleur Split lavenders.