No real difference between silver gelatin and pt/pd? I am... surprised. You probably know something I don't know regarding that, so I will not open my piehole too wide.
But when I split grade pyro negatives on silver gelatin paper, I see things happening in the highlights that I don't see with for example Xtol or Rodinal. It seems as though the color of the stain in combination with the Grade 5 Ilford filter have a relationship that doesn't exist were it not for the image stain.
Also, to resolve grain you need something like 4,800dpi full optical resolution. There are very few scanners that can manage that, which makes the comparison above a bit redundant, because you don't see exactly what happens in the grain department. You see an approximation and grain aliasing.
Not that grain is that interesting anyway...