My testing shows that diffraction on my d800e, which I believe have the same sensor, starts to get visible at around f/9. From there you have up to about f/13 where you can recover most of it with deconvolution, but at f/16 some detail is lost.
Unless you want to do focus stacking, I recommend setting the sharpen radius in camera raw to about 1.1, and the strength/amount to about 40-50. Keep the detail slider low maybe 10. Maybe pull the clarity slider up to 10-20.
Then do another round of sharpening in PS using the smart sharpen filter set to "lens blur", with "more accurate" checked. Use a radius around 0.9-1.2 and adjust the amount to taste. The smart sharpen filter uses deconvolution so it might be able to recover some more detail.
I highly recommend helicon focus, it´s very precise, and if you get the helicon remote app you can use a tablet as a remote control for your camera, which then does the stacking for you, and you get reproducible and predictable results.
I would not go below f8 when focus stacking, as you risk have problems with uneven sharpness. You don´t lose detail at f8-13, and if it´s a little soft you fix that with the procedure described above.