You can shave easily off the 8K but it does take practice to learn the stone and read it's signals. When you use the 8K side of the Norton no black swarf should show on that side at all. If you see any of this then the 4K side wasn't done yet and you need to go back. Also the stone needs to be lapped for a while to get the full potential. After you use the 8K (maybe 25 passes TOPS on that side or you can wire the edge that's if you did the 4K right), you can use diamond sprays if you want. That is a cheap alternative to buying Shapton 16Ks and other higher end stones. I actually heard from Jimmyhad on the phone once that some of the best edges he's ever experienced were from someone using the Norton and then progressing on diamond strops in increasing grits.