Just for our reference, the SP101 measures 1.350" at the cylinder. The cylinder on my new model Cobra is 1.404". Granted the Colt is a .38 and I don't have one of the new 357 models to measure.
The Ruger weighs one pound 9 ounces. The Colt weighs one pound 11 ounces.
Triggers (DA) are 8.5 for the Colt and 12 for the Ruger.
So it sounds like what we might need is a Clapp Colt Cobra.