How do you lap your Nortons when you first get them, and how often?

I lapped mine when I first got them, and after a couple thousand strokes, decided I either didn't do a good enough job the first time, or they were ready again. My regimen is sandpaper on glass and hash marks. I go through 220, 400, 600, 1k and 1500 grit. I also bevel the edges.

On my 4k, there was a piece of walnut under the sand paper that gouged the stone deep after only a couple of strokes, 'til I found it. I have a couple of loops that are barely visible. I don't know if I should lap them out or not, but so far it looks like the hone is doing it's job with them.

TIA

Goog