trigger45---
I looked at your list at end of your question, and checked your web site. Welcome to the wonderful world of "Concealed Carry" handguns. I trust you'll get replies expressing a variety of opinions so you'll have plenty of basis for making up your own mind.
The PPK about which you asked has magazine capacity of six rounds in .380 and seven in .32. The PPK/S holds one additional in each caliber.
These pistols were magnificent state of the art for decades--Solid, well built and dependable. The state of the art has passed them by. Historians, nostalgia buffs and students of firearms design still love them, much as they do the Colt Single Action Army, the Winchester 1873, the Luger P-08 and the Thompson Submachine Gun. Make no mistake, under certain circumstances, I think I could fight a pretty fair skirmish with any of these. They are simply no longer the number one choice for the job.
That said, the Walther PP series is still a good one--they are just a bit heavy for their power.
You asked about the calibers. The .32 ACP "standard load" is a .311 FMJ at about 825 fps. The .380 ACP is a .355 at perhaps 950. On the face of it, the .380 is a good deal more powerful. A larger diameter, heavier bullet going a good deal faster.
Some say the newest .32 loads are "equal to" or even "better than" the .380. The "stopping power" results may bear this out, IF you compare the Super Duper Whiz Bang over pressure loads with expanding bullets with the old .380 ball ammo. Compare apples to apples, though, and see what you get.
Due to the design of the PPK, the .380 can be a bit uncomfortable to shoot. This is a result of the shape of the grip area and tang. If shooter comfort is the only factor, the .32 might well be a better choice. If defensive use is the prime criterion, most people opt for the .380. There are several newer designs in more powerful calibers with equal or lighter weight, but you didn't ask about these. You can load a .32 PPK up with 60 gr SDWB JHP ammo and still not have a sidearm equal to a Kahr P9. But then, the Kahr is not the pistol that JamesBondAgentDubbleOhSeven packed in the later Ian Fleming novels. Just as our cowboy hee-roes didn't pack 1911s and Glocks and SiGs while taming the west.
Again, though, it is all about what YOU want and enjoy. Long ago but not so far away, I thought I was about to go visit exotic, scenic Southeast Asia, and one of my three personal gear choices was a brand new PPK .380. I never made that trip, but 34 years later I still have the Walther and the Randall knife.
Best wishes.
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---The Second Amendment ensures the rest of the Bill of Rights---