My 9mm carry ammo is 124gr+P Gold Dots. I have tested several different types of ammo, mainly for my PM-9 as it has a 3" barrel, and the GDs have always done great. The other ammo I would also be happy with is the Ranger T 124gr. (RA9T I believe).
I have been considering carrying Ranger T 147gr. ammo in the winter to offset the heavier clothing worn and give better penetration. However I would want to test them in the PM-9 to make sure they expand properly in such a short barrel.
Be well . . .
Another vote for leaving any +P stuff alone in your gun. Production quality varied a lot with those old guns. Some places produced good ones, while others had pistols that were built with slave labor and were poor quality, if not downright dangerous to shoot. (Hope you don't have one of those, btw!) You have a piece of history that is now probably anywhere from 68 to 75 years old. Don't take chances with it.
If you want to carry a hollowpoint load, you might want to try the Remington/UMC 115 grain one. Remington designed this load back in the 80s to sell to police departments and other law enforcement agencies that were still using old Smith and Wesson 9s and Browning Hi-Powers and other older designs that wouldn't reliably feed other hollowpoints. It has a rounded shape that is much like ball. I've run Speer Gold Dot 115s through a P1, but that was a gun that I'd done some "fluff and buff" on.
Buffalo Bore 115gr +P hollow points in my brand new Kahr CM9.