Let me be clear, I have absolutely no hands on experience with either the Staffordshire Bull Terrier or the American Staffordshire Terrier, let alone either of them crossed with a gamebred APBT, so my thoughts are based solely on my knowledge of what is my interpretation of the gamebred APBT.

If you indeed have quality bulldogs why would you think that adding either SBT or AmStaff blood would be in anyway beneficial ? I have read and re-read your post and am really at a loss as to how to reply with anything but questions of my own. I will ''say'' that I think adding either breed to an APBT of game lines is only going to produce dogs that are less then a gamebred APBT and something greater then a SBT or AmStaff.

I am not trying to be disrespectful to you in any way, just trying to understand your train of thought with what you hope to achieve by such a cross ?