I've only been reloading a few years, but I have done thousands and tested hundreds. I hoard them, well, because I love the shotguns.
When reloading, I noticed certain brands of hulls fit too loose with certain brands of 209 primers. They are not all exactly the same, brand-to-brand: not the hulls nor the new primers. After firing, the used hulls will vary, and sometimes a lot.
I have Winchester, Remington, and Federal 209s, and load a big assortment of used range hulls. Most are from me and my buddies, but I'm not picky and have reloaded lots of orphans left by other members.
I just select the primers based on which one fits correctly when pressed in. I run the hulls in matched batches, so I'm not switching primers all the time. If I get a primer that pressed too easy, I will usually knock it out and toss that hull, as a non-match, even though it might be from the same box as the rest. I want a box of shells to have all the same components, even if it ends up short a round. I hate getting a non-uniform performance, so I weigh each charge. I weigh the hulls, and toss any seeming too light or heavy compared to their mates. I don't care how long I spend to load a box, as I'm not doing it for profit.