Experience and recommendations on JNAT

[Bogie]

I recently came across an Ozuku Asagi (Koppa) stone. I bought this in 2019 and it was not flat! I left in the drawer until recently. I tried to flatten it with a 250 Norton. It was taking forever. I finally got it somewhat flat using the driveway concrete. The 250K smoothed it out a bit and went on to the 1K 2K and 4K Norton until the pencil marks disappeared pretty quickly. At the end of this adventure, I'm thinking it might be a good finishing stone after the coticule I'm currently using. Currently, I go from the coticule to a .05 diamond pasted paddle strop. I'm thinking the JNAT may be even a bit higher grit than the coticule since most reading sets the stone at around 12k.. Anyone have input regarding the use of this stone? I'm also thinking based on my reading I should seal the sidess and bottom with varnish or urethane. Sealing supposedly will keep layers of stone from fracturing. thoughts?

 

[Bogie]

Worked on this today and finished flattening it out. Seems the pencil marks didn't disappear as quick as I remember. I have a Japanese blade that was a little scratchy. After 150 laps on this stone it smoothed the edge nicely. I may add this after the coticule on my next sharpening adventure.