For the tile, I would start with a normal generated off of something like this, so you'd get some nice, large form detail. Then, using reflection (which should be masked by the grout and grunge), the normal would look quite nice. Only put more detail in the normal in some of the corners perhaps, or the grout areas, as you don't want the reflection being disturbed with small, noisy patterns.
The diffuse is looking interesting and quite nice, however.
