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rainman, what I end up doing is zeroing each individual gun to the ammo I am using. I have standardized on 147gr HST as primary and then 124 +P GD as a secondary, lastly HDY Critical defense as third option. Regardless of whether you are going to run the same ammo in all of your pistols or not I would recommend just selecting the same rears you want to use across the board then get a few flat black or serrated front sights, (since they are cheap) in various heights then slide the rears on all your guns go to the range. Shoot and then swap fronts out on each gun as you zero them to your preferred POA/POI at the distance you've selected and record the heights that work for the preferred POA/POI.
In addition I do the same with the practice ammo to ensure matching POA/POI to my carry load and the secondary ammo. That way I have options if I can't get something from one mfg. I can get it from another. This may seem overboard but it will keep you from chasing your tail trying to remember what was what later. Just a thought sorry for the long winded reply, I hope that you get things sorted.