NOTATIO

See
http://lilypondblog.org/2015/12/optical ... -a-swan-1/
http://lilypondblog.org/2015/12/optical ... an-part-2/
(unfortunately the third post is still to be written)

That last comment by OCTO is actually the keyword which I wanted to pick up anyway. I'm *very* late to that thread but wanted to add a number of thoughts, as comments to aspects discussed in this thread, and by adding some that haven't been considered enough in my opinion. And collaborative editing ...