I think your good since Winchester, tweety, and pancho are un related dogs you should be fine for some time. Personal opinion.
I would agree, gives you a pretty big pool of genes to work with.
I spoke to an old cat hunter who breeds his own dogs. He doesn't breed outside of his family, he doesn't care about relation other than his one rule of not breeding full brother to full sister. Other than that he doesn't consider relation in his breeding decision. He only looks at what dogs have and what they are lacking and breeds them accordingly. I'm not saying it is right or the only way to go but it worked for him and has been for some time.
He said the same thing when I asked him if he will outcross and he said, he will not outcross until the dogs start going in the wrong direction.
