Upon purchasing a batch of once-fired NATO brass for my 223 I segregated based on year for the LC, and three other brands. Weights were very different for the various manufacturers, as well as typical variability within a brand. Water capacity was not so different, and the POI at 300 yards identical regardless of anything. Now I mix all years of LC, but do keep the other brands separate just as a matter of good practice. This is not to say weight or more importantly volume does not matter, especially for different calibers. But I think you should validate the segregation for any parameter based on range performance to make the long-term effort worthwhile, and focused on what matters for your particular case.