Not bad. I'm a Gregorio user, but it's good to see something for the Finale users that makes reasonably attractive output.

You can laboriously make your own in Sibelius and save in a house style as one of up to 64 "notehead types". The last Alleluia above could be input as quarter-breve-whole-half, but the reciting tone and pes would then need a different notehead type. Some examples are:
http://www.cpdl.org/wiki/index.php/Canto_de_la_sibila (Cristóbal_de_Morales)
http://www.cpdl.org/wiki/index.php/Dis_tans_plus (Jehan_de_Lescurel)
http://www.cpdl.org/wiki/images/d/d2/Magnificat_primi_toni_%28Rore%29.pdf

Before I really knew what I was doing I did some hand-positioning of symbols & lines (2 parallel beam lines for the obliques!) in my Isaac editions:

http://www.cpdl.org/wiki/index.php/Dilexisti_justitiam_(Heinrich_Isaac)
http://www.cpdl.org/wiki/index.php/Summi_triumphum_(Heinrich_Isaac)

Still getting used to it, but I find it more comfortable to work with than Gregorio. I suppose it's just a matter of preference.

It's basically a plugin for Finale. It includes templates which automatically adjusts the staff lines. All notes are entered as quarter notes and the plugin automatically adjusts the meter. Once the notes are entered, you use the nume tool. It selects the most common groupings by default and one can cycle through various forms and even create custom shapes.

Best part is you can see the page layout in real time. Tweaking the spacing is still a little tricky, but I find it faster than Gregorio.

Does anyone know how to create red font text in Finale?

Mix, nice clean editions of the Isaac tunes. The chant is still in 5 line, non-Gregorian font with no reciting tones or final slightly longer note. I like the Finale plugin, as it is very clean, the cleanest I've seen. I still prefer my modified Anglican version of chant as it is the most legible for people who already read music. Things like double whole notes with hash marks on both sides are very difficult to read straight away unless it's on a line. There are only 3 basic note values: a black note (like a quarter note sans stem); a white note with head leaning right (actually a half note sans stem); and a larger white note with head leaning left (a whole note); and I use small grace notes with stems for any other small rhythmic deviation. I've found this reduces the chances for misreading errors, especially with my groups full of music readers and instrumentalists. The trick with Sibelius is knowing how to X-out stems for the whole piece. It's select all (command A)/shift/command/8. Also, for a line of text under a reciting tone, hold down the option key every time at the end of each word of text and hit the space key to make it stay under the reciting tone. Of course the words add to the left so you must grab the line and drag it over to a much widened bar to fit under the reciting tone. Here are samples we're chanting next week at Compline on Lent III with the ladies, which is very fast to imprint on my Sibelius 7.5. Tonight is Compline on Lent II, part of our Lenten Compline Series on 5 Sundays.

Jefe, I've essentially done what you do; same notehead values (although I use double-wholes sometimes if the phrase is particularly long) however I don't fret about rhythms as we just sing the natural rhythm of the text. Our choir has gotten pretty good about feeling things together (and I constantly harp, "sing it like you say it!").