I've previously always resorted to Sibelius, which works quite well as long as you don't need oblique glyphs: see Iste confessor on the penultimate page of St David's Vespers here, for example.

The link above can be made to work if one isn't put off by the unhyphenated example. Left box should look something like:
O come, O come Em-ma-nu-el,
And ran-som cap-tive Is-ra-el,
2. O come, O Wis-dom from on high
Who or-ders all things might-i-ly;
3. O come, O come, great Lord of might,
Who to your tribes on Si-naí's hight
4. O come. O Rod of Jes-se's stem,
from ev-'ry foe de-li-ver them

and the right:
initial-style: 1;
centering-scheme: english;
%%
c4 d f h h h ixgih g f. , g h f d f gvED c d. ;
--

I notice some bugginess, though: "Rod of Je- s- se's stem, from ev'- ry…"

Richard, did you use Medieval or another plugin to make that work in Sibelius? Or did you just have to place each neume by hand?

Good to know! "Jes=-se's" divides correctly, but I can't figure out how to get "ev- 'ry" instead of "ev'- ry".

In Sibelius one can use Symbols/New, choose font "Special noteheads etc." and create neumes to import to Notation/Noteheads/Edit Noteheads so that there's a single glyph per syllable. Then save as a ms. style. Maybe I should look into a plugin that will make oblique shapes; for this I repurposed an existing slash, and for this I resorted to the lines menu and fiddled.

Hi Gerard,

"Jesse's" doesn't divide, but of course you're right about "Jes=se's". But "ev='ry" gives "ev'- ry", which is a nonstandard placement of the apostrophe.

One question not addressed in the FAQ is whether one can get a void (instead of black) punctum for elisions. I suppose I should try writing Benjamin directly!

I don't know how to crop an SGV but here's what I could do with Ave maris: