Either will work...

I have used both, probably the Shapton more so in the Norton 4/8 into 16k then any other since it was my first "Finisher"

The Naniwa 12k just feels better and is a bit more versatile IME, so if I knew then what I know now I would chose the Naniwa


This is one of the advantages of using the Norton 4/8 or the Naniwa 3/8 once you get it tweaked you can go just about any direction you want to now