I just literally started honing for the first time, so take this FWIW, but it's consistent with another thread here on lapping Naniwa stones http://straightrazorpalace.com/hones...-not-flat.html. I took out a new 12k today and was going to lap with a new Naniwa lapping stone. But having read the thread I decided to check. Good thing cause the lapping plate was out way more than the 12k stone.
I do machine work and have a precision granite inspection table, so I put the lapping plate on with wet/dry paper and saw the high spots. I didn't have coarse enough paper to bring it down in a timely manner so I drew a grid on the 12k and put it on the paper, didn't take a but a few strokes to get all the marks off. But I guessed as much when I set the thing dry on the granite table and it practically stuck to it.
Didn't mean this to be end all be all but just my one experience today.