The problem with carrying an SA revolver for CCW is the gun cannot be put into a "state of ready" with a safety activated.
Not to preach to the choir, but a DA revolver is always ready to go with simply a pull of the trigger; the relatively heavy & long pull being considered a type of safety in itself. A DA semi-auto is similar, it may or may not have a safety also. SA semi-autos have a safety designed to be activated when the hammer is pulled back.
In each case, you can bring the gun to bear onto target in a state of ready with a mechanical system that safeguards against a nervous trigger finger. Once you pull the hammer back on a single action revolver, it is ready to rock & roll with little effort and must be pulled back for additional shots.
But - if that is what you want to do and are willing to work with it, I think that something betwen a 4.5" to 5.5" barrel would be the best compromise. For CCW use, I prefer fixed sights & practice with a "cheap load" that hits to the same POA as my carry load. As far as caliber, I'm wondering if .41 Mag wouldn't be the best choice - assuming you can load your own.
Have fun deciding!