the amount of white you get seems to be random, thats what most people say, but im not sure. We now basically have two pied genes, pied and leopard, and animals that look pied can be homozygous pied, leopard pied, or homozygous leopard / super leopard. Maybe its just a coincidence, but ive seen pics of several snakes that where 90% white, basically all white except for the head, from ppl working with the leopard-gene.

anyway, my assumption would still be that its random.

the non-white parts of a piebald can be influenced by all kind of genes when it comes to color and pattern, but the white just stays white, even if you make the rest really dark.