Geschichtliche Darstellung der Entwichelung der Hessen-Darmstadtischen Truppen ... 1840.https://drive.google.com/file/d/1az-JMWzTumbHjDNKrCX6tZ0hkgJMk_5_/view?usp=sharing
seemingly only for zoner
Very interesting but the link leads me to the regimental history of the 12th Bavarian Infantry regiment - however not complete but with a chaptaer - not about the Hessen Darmstadt Truppen, but for me even more interesting about the
Die Großherzoglich WÜRZBURGISCHE Infanterie 1806 - 1814
In case you have a link to the full regimental history it might be worthwhile to check because it seemingly has chapters of those units it was made of.