I have a PM9 , it is my EDC, currently speaking. If I'd do it all over again... and if I'm fixed on Kahr and would not consider any other, I'd go with P/CW 9.
Especially if it is NOT intended for pocket carry, the extra length in P/CW made absolutely NO different in conceal IWB carry (just get a quality IWB, such as Mitch Rosen, HBE, Alessi, and the like..). The narrow width of Kahr makes it perfect for IWB.
Your friend has big hand? The longer grip in P/CW does make a HUGE different in shooting.. the very short grip in PM is already too short for my smallish hand (and the ugly gap between the grip and the mag base plate pinches my pinky).
Rent both, let the hand tells the truth.