Wasnt it supposed to be compare without microscope? I tried that route at both around 400 and around 1K stones, and could never reliable determine which was finer, one looked finer but worked rougher. I also tried laying a bed of scratches with stone #1 and polishing out those scratches with stone 2, then polishing those scratches with stone 1. I though I might discover something with that, but no, if they are similar they polish each other out about the same. If this stuff is pretty hard to determine at these low grits, how to you think they will pan out at finishing grits? Even with a microscope, how do you plan to compare depth of cut vs width? I know you dont like the answer, but using them will teach you the most.