FWIW, I've heard of at least one alternative style campaign structure that employs Stone Runes in place of scrolls and the like, so those would be heavier. I can also imagine lighter ones, say using something lighter than vellum or paper (which is more of an early modern technology anyhow). I've personally handled some scraps of Papyrus thousands of years old as well as illuminated Vellum from the Middle Ages (I used to work in a museum)--Papyrus is considerably lighter than Vellum.