I am not sure what you mean by a direct outcross that would be only 50%.
I am also not sure what you mean by "a direct outcross breeding off HIM" ...
Breeding off of whom? Nigger? Nigger's been dead for years.
I also don't know what traits Mayfield's Nigger had as an individual, either.
(CYJ may actually be able to help you there.)
I am trying to make sense of what you said.
Sometimes it's helpful to spend some time actually organizing your thoughts.
I guess the first thing I would ask is, "What traits does the bitch have, herself?"
And then I would ask, "Are these traits she has the traits you're looking for?"
Jack