Feel free to correct me, but I believe Ruger (or any other manufacturer) only warrantees any gun, including the original Vaquero, for SAAMI-spec'd factory ammo, at least officially. I have never handled a New Vaquero and don't hot load my originals, but I have read
numerous places that the New Vaquero is less robust than the original and will not handle the "Ruger only" loads safely.
The way they did this was to reduce the diameter of the imaginary index circle that passes through the center of all chambers. This means the wall thickness of the chambers is increased in spite of the cylinder diameter being similar to the Colt's SAA.
If you do this, aren't you basically putting the chambers closer together, thereby making the walls between the chambers thinner?