Professional men all agree:
.38 Special +P.
I have argued this for many years. If you are talking about deep concealment, then the S&W 638 Airweight Bodyguard is THE CCW.
If you are wearing a suit, then you have a lot of freedom. If you take off your suit coat and/or waistcoat/vest, then you can't hide a standard length handgun anymore. Fitted shirts and trousers don't help conceal.
As a right-handed person, I carry a S&W 638 in my RH trouser pocket. I use a "pocket holster."
This goes to the "something is better than nothing" philosophy. When I enter the court building, I have to check my 638 before the metal detector. (We have lockers similar to the YMCA, etc,). When I leave and hit the street, I armed. I have never been "made" with the S&W 638.
The 642 and 638 are more or less similar. I prefer the 638 because it would theoretically help with aimed shooting. I