In my humble opinion, I think the direction that nonstaff elements
are looking is a very important foundational concept that should be
included in the Notation Reference documentation, the Internal
Reference, and perhaps even the Learning Manual, and some snippets
could be added to the Snippets Library (like the beautiful one you
wrote in this email). I would also like to suggest that the ability
to choose which direction nonstaff items are looking could be added
to future versions of LilyPond. [...]
Care to prepare a patch? You seem to be a native speaker, and being a
novice helps a lot in finding the right point of view for the
documentation...
Werner