I routinely do focus stacking in shooting landscapes. So, whereas the programs for macro are great, I use procedures that are more casual.
Keeping in mind that only a thin plane is actually in focus at any aperture, the issue is how much out of focus one can tolerate and where the focus should be in light of the composition.
With respect to the camera scales, they are all, in my view, based on a snapshot size print. So, adjust for the print size.
In practice, what often works best is to simply focus on the main points of interest. Viewers are going to tolerate some less than perfect sharpness in the unimportant parts of the composition.
If the air is perfectly clear, as in the High Sierra where I've done a lot of shooting, the ridge line can be critical. So, I often use the infinity stop (if there is one, and that is one of the criteria I use in evaluating lenses) as one of the points of focus.
With wide angle lenses, a dual focus approach works amazingly well, even if hand held. But I also do not expect the automated stacking programs to work.
Since we are not talking of saving film, I often take more shots than needed and throw out the excess ones.
The image on the top of my web page had 3 focus points, is 3 (overlapping) 35mm (Sony a7r) frames wide, and a few extra shots to get the sun right. All was hand held, manually stacked after an edit>align layers, and stitched in PS CC.
Paul
www.PaulRoark.com