Kerncat@
Federal primers are the softest. With your hammer-fired CZ pistols, you can lighten your trigger pull by lightening the mainspring, and anything down to a 13lb mainspring should set off any properly seated primer. But as people go lighter than 13lb, to lets say an 11.5lb mainspring, some of your harder primers might not detonate every time, and when you go down to the 8.5lb spring, people have found that the Federal primers are the only ones 100% reliable, and that is only if they are seated properly.
So the reason you see people fawning over Federals is for their softness. If you run a 13lb mainspring or heavier, you have no worries with any primer other than just setting it fully.
As to Angus's load being tuned to his gun, I'm sure it is, but some of your concern with not anticipating similar results -- that's one of those things that is 100% true for rifles where you're shooting hundreds of yards, so even tiny ballistic differences can play out into big differences by the time the bullet arrives at its destination, but for pistol shooting, it's not as likely to show up as clearly, if at all, for sure not with pistols of the same manufacture. If the barrels are of the same metal and the rifling cut or pressed or forged with the same tools at the same factory, you're likely to see very similar precision from one gun to another with a particular load. I'm not saying there's nothing to be tuned in that case. We should definitely tune, but if Angus's load is stellar in his pistol, it's likely to be at least very good, if not equal, in every other CZ pistol with barrels of similar manufacture, within +/- .1gr of powder and +/- .010 OAL.
I'd point to Joe L in this matter, the bullseye shooting regular in the forum. He buys Atlanta Arms 9mm match ammo. It's not tuned to his pistol. And he can shoot sub-2-inch groups at 50 yards. It's a great load that works well in just about everything.
There are standard target loads for .38 special and 9mm and .45 that seem to work with just about every pistol, that MAYBE get varied a hair. Because it's pistol. And we're typically shooting under 50, if not under 25. So there's just not a lot of variation to be had at close range.
You MIGHT find a that someone's stellar load for their 75 doesn't work well in yours, but I wouldn't gamble on it.
Hope you find this useful.