a little late to the party but...
For the LARGER 25 acp vs 22LR handguns, I'd go with 22LR just for less expensive ammo = more practice. 25 acp is better sealed, and hence 'ages well' but honestly for the price of 25 acp ammo you can afford to put new 22LR ammo in monthly and STILL come out ahead.
Now, if you were going to be carrying concealed in very 'personal' places rather than in a pocket holster, ankle holster, or a gun in a purse, then the 25 acp comes to the fore because the smallest semiautos are in 25 acp only. (Baby Browning and such) and if you have to deep conceal then the small factor outweighs the other factors.
HOWEVER there may be some other options. The Beretta Tomcat is a slightly larger bobcat in 32 acp. Sig made the P230 which was an 'improved Walther PPK' in 32 acp. They have since switched to the P232 which IIRC is in 380 only, but a used P230 in 32 acp might be a solid choice.
380acp in very light guns can have some snap. However 380 in larger handguns can be quite tame. Beretta has the 80 series of 380 pistols. I have had personal experience with the single stack (I cannot always keep the model numbers straight) which was quite slim and easy to hold and a real pussycat to shoot due to the gun being relatively heavy for a 380. Similarly, Browning makes/made nearly the same thing called the BDA except IIRC the safety was located in a slightly different spot.
A while back apparently Beretta actually had FN/Browning make some BDAs for them under Beretta's name in 32 ACP for a large police contract. (I don't know who but I have been told the Tokyo police were for a while issued Sig 230s in 32 acp) And these came back as surplus about 10 years ago. IF the BSA or Beretta model 80s in 380 are pussycats then the 32 acp version would be a kitten. I seriously considered buying one for some recoil sensitive family members partly based on my previous experience with the Beretta model 80 series.
Similarly the great CZ-83 is also available in 32 acphttp://www.cheaperthandirt.com/2CZ8391305-1.html
Also apparently Bersa's copy of the Walther PPK is also available in 32 acp. And of course the Walther itself, you should be able to find that in 32 acp.
NOW, an entirely different option is a small frame revolver in 327 magnum or 32 H&R magnum, using 32 long ammo for practice. You can get a 3" barreled SP101 which would have quite a bit of heft and really tame even the 327s, or I believe both Taurus and Smith&Wesson make a lightweight version in 327 magnum or at least 32 H&R mag, again, load with 32 S&W long for very low recoil practice.