Honing? Try the sidewalk, it works!
After seeing a few threads about flattening stones, I thought I would share a solution that worked for me on a JNAT. The stone I recieved seemed to be a decent stone but it was quite far from being flat. I worked it with every grit I had down to a 250 grit Norton. Still the shoulders were not flat and there were hollows. I finally, after some consternation took the stone in the front yard and used the concrete sidewalk to flatten it. I ran the garden hose out to the walk and kept it wet and after a short time the stone was reasonably flat albeit many deep scratches. I then went after it with the 250 grit, 1K grit and finally got it smooth and flat. Subsequently, a 4k, 8K Shapton smoothed it out nicely. All that said, the original condition didn't leave many options. I hope you don't find a stone that needs a sidewalk, but it can be an option.