I see that natural stones leave a different finish on the scope. I looked at one on a dialed in coti. It was smoother than what I got off my cnat, and the ultimate shave test was the coti edge I could shave with all day and night, the cnat was dullish. Im sure if I work it some more I may get something more out of it. I don't find any issues with lapping with my dmts. Ihave 120, 325 600 up to 8k. I use the 325 usually unless I have a lot to do and then I swithch to my 120. But I always finish on the 600. They cut steel no problem. I always lap under running water and with light pressure and have no issues to date.