I see incorrect numbers for 357 Magnum from a 2" barrel.
http://hipowersandhandguns.com/38vs357snub.htm
"A Ruger SP-101 averages 1278 ft/sec with Triton 125-grain Quik Shok +P ammo"
It is best to chronograph your loads out of the short semi-auot in 9x19mm and the snubby 357. I think the snub nosed 357 will still get 1200+ FPS.
The pocket gun is all about concealed carry and not about maximizing effectiveness. If you want to maximize effectiveness, buy a Glock 20, add a 6" barrel, and shoot extremely hot 10mm ammunition. You'll have 16 rounds of 10mm onboard and another 30 in two spare mags. The pocket gun cannot do anything like that unless you wear overalls with giant pockets. Then the Glock 20 fits in the pocket, though DeSantis has yet to release a Nemesis for it. I'm sure a custom holster maker could build one for your pocket 10mm.
I would consider any J-Frame in 38 Special +P, S&W 640-1 or S&W Model 19 in the revolver. The Glock 26 is my first choice in small 9x19mm guns. Many companies are releasing small guns in 9x19mm. Look at the Kahr PM9, Keltec PF9, Ruger LC9, and SIG P938. Reviews are outstanding for the SIG P938. The SIG P938 is a very new gun and you may want to wait a year so they can work out the bugs.
I have owned several Kahr PM9 pistols and only one was reliable enough for carry. I had problems with the Kahr K9, but it shot very well when it decided it was a good day for shooting. If you can get a good PM9 (used from a friend), then go with the PM9. They carry really well and are very accurate. Night sights are an option.
The Keltech PF9 looked very rough internally. It did not inspire confidence. The trigger was substandard and difficult to use.
The trigger on the LC9 that I tried was yucky. It appears to be an improved PF9--it seems to be intended as direct competition. I recommend researching the gun extensively before buying.
If you have no idea what to get after all this, just buy a S&W Model 642 or 442 (38 Special +P) without the lock and call it good. Don't agonize over a few FPS. Just buy expensive ammo from the best manufacturers (Corbon, Speer, Hornady, etc) with a weight of 130 grains or more. I spent the other day looking for defensive 38 Special +P ammo and most companies seem to be making short barrel loads with 130-140 grain JHP bullets. Choose several that seem to look good, buy a box of each and run a few tests with the chronograph. Pick the the one that shoots best for you. Buy 10 AZOOM Snap-Caps (so you can practice reloading from a loader or speed strip) and dry fire the gun constantly. The trigger will improve as it loosens up and your finger gets stronger.