I need to lap my Norton 4k/8k stone and I am wondering what kind of sandpaper, and what grit size to use when lapping it.

Also, Do i need to lap the 8000 side? If so, do I need to use a different git size? Lastly, if the same grit size is acceptable for both the 4000, and 8000 side, will it hurt to use the same piece of sand paper that has been used on the previous side, since it will have some of the opposing grit contaminating the sandpaper

Thanks!