100 sheets of stolen vellum

[LisaFaginDavis]

All of the parchment is of similar quality. There is no difference in quality from one section to another. And - to respond to an earlier comment - the parchment is so worn that it is nearly impossible to distinguish hair side from flesh side, so we can't ascertain whether it follows Gregory's Rule or not. I'm fairly certain it doesn't, especially since if the manuscript was indeed intended to be a loose pile of un-nested bifolia (i.e. singulions), the distinction between hair and flesh sides from one bifolium to the next would be irrelevant. There is no evidence to suggest the manuscript was produced over a long period of time.