I really like the description/script analysis of "Remains of a Medieval Anthiponal" at
http://www.brown.edu/Facilities/University_Library/libs/hay/focus/antiphonals/
done by Brown University Libray as one of a series of articles "Focus on the John Hay Library"

The Antiphonal's script is a gothic rotunda (littera gothica textualis rotunda italiana formata), not gothic textura quadrata, but the information and it's layout is interesting and relevant.

I've read lots of descriptions of various scripts now and this one is about my speed
http://www.brown.edu/Facilities/University_Library/libs/hay/focus/antiphonals/script.html- talking specifically about letter formation, different forms of letters, ligatures and biting bows.
- placing the script of the antiphonal into it's historical context.