I am lapping with 400 grit wet and dry on glass. I did bevel the edges with a 400 stone.
I prefer the 12k edge to the 8k Fuji one.
I do not have any real naguras and I am not sure if I will invest in them; not right now, anyway. I had a small hard slurry stone from a friend that I've slurried with. Now I have an Eze-Lap diamond plate for that purpose. It is a small plate, 1200 grit.
I did notice the load up on the 12k, but I do clean it every now and then. I finish under running water with the lightest of pressures and then it does not load up anymore.
My 30X loupe is still on it's way.