Velocity/Power Factor for Snubby Practice Ammo

Mods, if you think this should be somewhere else, please move it there.

I've settled on 125-grain ammo for my 642 because that's what hits to POA. From what I've read, chronographed velocities of good defensive ammo in this weight run ~850 fps +/- from a snubby. Conventional wisdom holds that practice ammo should be loaded lighter to keep from beating up the shooter.

Is this CW BS? I didn't find the recoil from WWB +P 125-grain JHPs and R-P 130-grain hardball that bad.

If it is in fact a good idea to download practice ammo, about what percentage of defensive ammo's power factor should I aim for? Or is this just a shooting equivalent of "how many angels can dance on the head of a pin"?