One of the finest mold and sight makers in the World is right on my doorstep. His name is Mike Newmann and his molds and sights are used extensively in international black powder competition. Would be happy to get him to quote you if you want. Also, if your ten gauge is black powder, don't forget that you are playing with linear pressure on ignition. That will put your barrels in danger of bulging or blowing if you inrease the weight too much. My experience is that you should stick to the recommended weights on BP.