NOTATIO

You are definitely on to something there, OCTO! I just fear that the multimeasure thing could be a bit risky too: ...

Useful symbols in parts like this: (short rest), or (shortish rest), or (not so short rest), or (long rest).

Well, it's difficult to say anything on the grounds of so patchy an information.

Or, the X with bracket could refer to a footnote somewhere in the score, or to a comment in a preface?

It would be interesting to know who made this change for the first time. The composer himself, or a conductor in contact with Janacek?

Nostalgic, in more ways than one.

There are also the different contexts of system break and page break. In the former, as in one of your examples, the repeated arrow doesn't seem absolutely necessary, while when ending a page, to me, it seems more needed, or informative.

OCTO, this may be small matter in your very well thought-through engraving. But I wonder about the horizontal line in m. 221 continuing with an arrow on the next page. As it is written now, the line might be conceived as an extension of the ord. at the start of it. Assuming that you want a gradual c...

And of course I agree with OCTO. In parts readability and playability is everything. Never mind the white spaces. My impression is that today's music publishers don't count the pages as miserly as they did in the past.

I've wondered why music engravings should be so different from books in that respect.

Even with good publishers you see a lot of empty space after the ends of chapters. "Selling paper".
OUP: Harper Collins: