Let me start by saying, Beautiful Hone!!

I use an Ohira suita as a final finisher and it is the best I have used out of all of the j-nat that I have previously owned.

As to its suitability to be a final polisher, you are going to have to put it through some honing tests. It might take a few weeks to find the time to do them all but afterwards you will have a good idea as to its overall suitability.

Try it without a slurry and lots of water. Try it wilth a spritz of water and hone nearly dry. Try it with a light slurry. Try it with a medium slurry. Try it with a heavy slurry. Try it with a slurry and hone until it gets thick, then water it down with a light spritz of water; repeat as many times as it needs to gain a uniform colour to the bevel.

I have found that my suita is as excellent a finisher as anyone can get. Have fun with it. Don't rush it and flub the results and get rid of it before you know what it is capable of.

I wouldn't use any Mikawa Nagura on it as the particles may not completely wash off (getting trapped in one of the 'su' pockets).