What I was going to do is to start with a pair of Rocks and a pair of Shamo and start two lines and then breed them back and forth. You should know in a couple of generations what you have.
A Rock rooster over a Shamo hen and a Shamo rooster over a Rock hen. Then breed the offspring to the same of the other line to define them.
A Rock rooster over a Shamo hen and a Shamo rooster over a Rock hen. Then breed the offspring to the same of the other line to define them.