I think the concept that “grit is grit” is essentially correct. I would add that hardness and friability of grit are important factors in determining the depth of the scratches and how those extend out to the final edge as teeth. Some abrasive manufacturers actually rate their products with an AR (average roughness) scale to describe the peaks and valleys of the surface rather than the particle size. Other factors are the substrate pliability which can mitigate the effects of super hard abrasives like diamonds and can also modify the geometry of the edge, providing curvature. Additionally, leather has the very unique function of burnishing; smoothing the surface of the steel through plastic deformation. I’d translate all that to say that grit for grit, the scratch widths should be the same, the depth will vary based on hardness and friability of the abrasive, giving the final edge more or less teeth. A flexible substrate like leather will give curvature and only leather or super hard, super smooth metal will burnish the surface. The leather with a good micro-abrasive is an unbeatable finish IMHO for most applications except when you want a very toothy edge.
