@Jim, Alan, Hans, and others. Thank you all for such insightful comments and supporting each other towards consensus even while maintaining a difference of preference.
@Hans: Thank you, Hans, for such a succinct and insightful post about how you approach your use of lenses. After reading your comment, and the responses by Alan, Jim, and others, I have come to understand much more clearly my preferred approach to the selection and use of lenses.
From your comments I can see that my preference is for the method, as Alan so well puts it, "...to see the shot and then pick the lens that best captures it", rather than the other approach of first choosing the lens and then going in search of the shot that best fits it (if I understand you correctly, Jim).
So, to answer my original question about finding a focal length to fit one's vision: I think that this discussion has expanded on this to conclude that it is a focal length that best captures the vision in that moment.
So, in conclusion, yes, use the focal length that matches how I see. Whether that is choosing a telephoto to pick out particularly pleasing patterns on a hillside, or a wide-angle to capture beautiful folding foothills approaching a mountain side.
@Hans: Hans, you mentioned that, for landscapes, you only use full-frame cameras. I think this is an interesting point to make and I reflected on this in light of my recent concerns about the resolution and image quality of m43. Particularly as I contemplate committing myself further to the m43 system through the purchase of additional expensive lenses.
Perhaps I should continue to utilise the image quality of the E-M1 as best I can until I have a need to go full-frame, and not worry about over investing in m43 lenses. Certainly, by all accounts, the top lenses available for the E-M1 (from the 43 and m43 range) are far better than anything available from Canon or Nikon for their APS-C cameras, and possibly comparable to some of the top lenses for full-frame. By the time I come up against the limits of m43 there might be a new sensor that could allow me to continue with my investment in m43.
The other option is to buy something like the Sony A7/A7R and excellent second-hand manual focus lenses - specifically for landscape, and keep the Olympus kit for everything else.
BTW, Hans, your images are absolutely wonderfully beautiful.
Thank you all, again.
Cheers,
Nick