I am in the process of lapping a surgical black so I'll share what I've learned. These stones are so hard that I wouldn't even try to lap it on my D8C, if I had a XX coarse maybe. It wore out a sheet of 220 wet/dry getting just one side of this thing flat. Ater that I'm lapping on progressive finer grits, 400, 800, 1000 to smooth it out. This part is not nearly as tough as getting it flat in the first place but it is still a chore. BTW, I'm lapping a C12K too and in comparison the C12K is like lapping a norton 1K waterstone. Good news is it will probably never need to be lapped again in your lifetime.
Do not meddle in the affairs of dragons for you are crunchy and good with ketchup.