Typesetting em dashes in lyrics - best solution?

[Schonbergian]

I've been working on typesetting a hymn using a text from Newman's Verses on Various Occasions, which (unusually for a hymn text) uses full dashes, even over lines (for example, the first line of verse 2). I've struggled to typeset this properly and have arrived at what I thought was the obvious solution, yet still leaves me wanting more. I'm wondering if adding LilyPond's dashes (similarly to if a multi-syllable word was broken across multiple notes with space in between the lyrics, as can be seen in other areas of the score) would be a superior solution. I'm just not liking how the dash looks right now and feel that it should encompass more of the space between the lyrics it joins.

[John Ruggero]

Deleted post.

[liuscorne]

In modern book typography, the first case would look like this:

[[American English: em dash, no space]]
Then would Thy name—the Just, the Merciful—
Strange dubious ...

[[British English: en dash, space before and after dash; in the example below the en dash looks rather short, it should be longer than a hyphen]]
Then would Thy name – the Just, the Merciful –
Strange dubious ...

I'm not sure how to deal with them in a score. The way they are used now is confusing (John thought they were extenders) and looks wrong judging from a typographical point of view. You might try to keep the em dash and center it between the surrounding words (name — the) or add space before the em dash (Mer - ci - ful —). Since the dashes enclose a paranthesis, you might use commas instead of dashes.

In the second case (of heaven,—) I would simply add a space before the em dash.

[Florian]

Coming a bit late here… I agree with liuscorne, and I'd probably prefer to center the em dashes between the surrounding words. They are long enough to be easily discerned from hyphens.
I just wanted to add that in any case I would make sure the syllables or words are centered under the notes and not offset to the left because of the dashes.

Is there a particular reason for not using system brackets? Just curious.

[Schonbergian]

System brackets are not typically used within this context in modern hymnals.

Perfectly centering the dashes will take some work but seems like the best of a less-than-ideal group of solutions.

[benwiggy]

I'm trying to think of another example, where I have seen em dashes used within lyric lines. And I can't come up with a single one. Which may be indicative of something in itself.