I think there is some confusion about the idea of sharpness. At 30x20, assuming proper darkroom technique, should produce sharp grain from 35mm, but this is not easy unless alignment of everything is spot on. Yes, sharp grain, But the image will be limited in resolution by the grain and will not actually be that sharp itself. I sometimes hear people talking about 'grainless' 20x24s from 35mm FP4/TMAX100..... This aint happening! It will only be so if your darkroom practice is such that you end up with a soft image and the grain is not focused sharp, or you use a diffuser under the enlarger lens. Some of Salgados images were from 400 film and were printed big. However, this was in a gallery where the viewing distance was far more than the average home, so there was no issue.
Tom