My point Bernard about stopping down one stop for good measure and not worrying about diffraction is that if your DOF aperture setting or focus point is off a little, it's worse to have parts out of focus with no diffraction rather than having everything you want in focus but with some diffraction.
Which do you think is worse and under what conditions? Are there differences between medium format film that I shoot and D800 digital?
When T/S lenses and DoF stacking are not applicable then yes, you are of course correct that stopping down is a good solution. My tongue in cheek point was just that it hurts to spend a lot on top lenses and not really tap into their resolution potential. But artistic result is of course more important.
Nowadays, my preferred approach is a combination of 2 rows stitching and moderately stopped down image for the foreground that is focused closer than would have been with a single image. Live view is indeed the easiest way to find the optimal focus point both in the foreground and near infinity for the upper image row. The technique can of course be generalized to multiple rows.
I am in the process of writing an article to describe this technique that, as far as I know, I have invented. The image belw was shot with a D800 and the Otus. 2 rows pano, 8 images total.
The key difference btwn film and digital is how easy it is with digital to see that the resolution potential of the lens/sensor was not tapped into.
In the end it depends on the print size you are targeting for a given series of images. If you print at A3, then stopping down with good sharpening is all you'll ever need.