The Colt SAA grip is basically smaller in every dimension, and in most cases thinner. It is similar to the very earliest Ruger grips.
Some of the CAS/SASS people are shooting expensive genuine SAAs or fixing up Italian critters of the same size because they're faster-handling. With this grip choice on a Vaquero, and a 4.6" barrel in .45/.44cal for less weight than a .357, you should be able to get something that handles VERY similarly, but much tougher and with the modern transfer bar for six-up carry.
Cost on a Vaquero with that grip and maybe minor additional mods (free spin pawl, poor-boy trigger job and a Belt Mountain basepin) would be FAR less than an SAA, and comparable with some of the high-end Italian guns that are tuned up by good US gunsmiths and sold that way, or you had it done. And the Vaquero could shoot over double the horsepower levels.