Shooting Times expert Skeeter Skeleton once wrote that if he were forced to choose just one handgun it would be a 5" S&W model 27.
I finally went to a 5" 629 and I am very happy I did.
There is a Speer reloading manual that has a page of "real" chronographed velocities. That full page with tiny print contains many examples of shorter barrels outpreforming their longer barreled brethern. In my own small collection of handguns there is a 4" that beats its 6" brother by roughly 100 fps with the same load. The same holds true for a 5" that does the same to its 7 1/2" brother. Until you run a firearm on a chronograph- you are guessing! Good luck!