Line breeding ?

It's just my opinion, but there are a lot of variables in this equation. When you add the fact that the dogs are crosses between two breeds as different as curr and bulldog it's even greater. I'm not knocking it just a fact. I have never been very fond of the mother son mating. I was told by old dog men that were very successful not to make the cross and I did it anyway. The results weren't good. It was a line breeding with my family of bulldogs. It's not such a big deal, I don't think, if you are only breeding for a single trait and are not worried about everything else. That's not what your looking for. If I were trying to accomplish what your doing, I would breed the dogs that compliment each other from this family. An example might be the female might have all the desired traits you want except she is slight in the grit department. The male is the same except he is too gritty. For me these dogs would be father/daughter, uncle/niece, cousins, grandmother/grandson, aunt/nephew, even a half brother sister on the side I was trying to breed towards. I would use a dog that was just a little over the line in the grit verses one that was extreme. My experience says not to use the ideal dog to the gyp that is lacking because it will put you right back to where you started, wanting more bite. But, like I said earlier, how tight your gyp is bred will have a major impact and just because you breed to one dog out of a litter that isn't too rough don't mean that he isn't the one in his litter that produces alligators. That's the difficulty in raising crosses, more trial and error. I surely don't know it all this is what I have observed in my attempts of raising dogs. One other thing is once you've raised what your looking for, you gotta start breeding like dogs to one another and prioritize your traits. This genetics thing gets real deep real quick. Learning how to set a gene pool ect. Good luck!