I just run my Oregon blademaker with 400 grit. For a razor edge, I turn the belt inside out to take off the wire edge. I know it wasn't what you were looking for, but I sharpen a lot of knives. Friends and coworkers found out I can put an edge on about anything and bring them to me. It is also nice to use at the fire house to keep axes and wildland tools sharp.
As for diamond sharpeners, I have used the thin ones with plastic backer and did not like them. I like the one from harbor freight that has the box with one mounted on each side. It does not flex and holds it on a bech quite well woth the feet.