Welcome to the forum!
You referred to pocket carry, Which indicates a smaller weapon, so the Short Barrel Speer Gold Dots would be a good place to start. NYPD has had good success against bad guys with the .38 +P version, and the bit of extra speed from the Magnum can only make performance better. We have had one local shooting incident with the Magnum version, and the decedent died instantly. He didn't even live long enough for his heart to pump blood all over the place. My wife was the on-scene forensic investigator for the M.E., so this is not some war story pulled off the Internet.
Second question. I like revolvers for some IWB carry, there being a couple of points on each side of my anatomy that accommodate the contours of a revolver quite well. I prefer, however, a holster like the Milt Sparks PMK, outside the waistband.
To expand a bit on pocket carry, keep in mind that bad guys do not usually announce themselves from across a street. The first clue of an attack may be the first hit, or the sudden appearance of a weapon in your face. Body alarm reaction makes us crouch in such situations. Getting to a pocketed gun can be very problematic in such conditions. It can be very comforting to have a hand already on the grip of a pocketed snubby, as one passes through a particularly bad area, but living life with a hand constantly placed thusly is going to be quite limiting. I like a pocket rig, with the Kramer rig being a great one, but
not for my only handgun.
As for the ballistics question, I won't get deeply into that. There are discussions on that subject right here on THR. I tend to stay out of such discussions, knowing the .357 Mag has done well in the real world, repeatedly, including one summer night in 1993, for me, when one shot totally and instantly changed one bad guy's channel. (125-grain JHP Federal silver-box Classic; Ruger GP100, 4" barrel)
Fanboys of the .357 have exaggerated its performance, and is detractors have fired back with criticism that was not always fact-based. That is the nature of the Internet. In my region, various agencies have used the .357 to good effect, enough times, that I have no problem selecting a .357 weapon to defend my life. keep in mind that modern defensive cartridges are largely engineered so
that the bullets perform much the same regarding penetration and expansion. People are still supporting arguments with data that is quite simply out of date. For example, older 125-grain
bullets tended to fragment violently, while all modern bullets tend to hold together. Older bullets in
many other weights in the various cartridges tended to not expand as much as a defender might
desire, but newer ammo tends to be better; expansion is commonplace these days. Keep in mind, I
just have to ask the Missus about such things; she says expansion is the norm with JHP ammo, in
all the common defensive cartridges.
Well, looks lime I said a bit about ballistics, after all. Note, however, the lack of numbers and figures.