Is the VM an autograph or copy?

[Scarecrow]

Keep in mind that the time period was feudal, medieval Europe. Late medieval yes, but still a feudal society. It would not have worked the way we imagine it today with a wealthy capitalist hiring a group of wage workers. It would have been a feudal lord with a noble title who had a large retinue, like a small army of servants who pledged their loyalty only and exclusively to him and his family, their liege lords if you will. Sure, the system was beginning to fray at the seams after the Black Death, but the feudal social order still existed in the 15th century. 

Of course, that also depends on where the VMS was made. If it was made in the Republic of Venice or Florence of the period, the things were different. The city states had already well organized espionage and intelligence networks, state inquisitors and other thing that any one producing questionable stuff would have been afraid of. 

Again, I acknowledge that this old feudal social order was beginning to fall apart by the 15th century, and by the 16th century it was replaced with a new social order. But those would have been the social expectations that everyone had and that everyone was expected to maintain and live up to. 

So to get to the point, I expect that in this scenario, the few trusted scribes and clerks who were given the task of performing the actual physical writing of the text of the secret cipher manuscript in the secret script would have been entrusted with the secrets. Perhaps different sets of secrets for the "Hand 1" scribe writing in "Language A", the "Hand 2" scribe writing in "Language B", etc.

Agreed, this could been one of  the reasons to have more hands doing it. But still all of them should have been trained to the system, possibly taking notes and learning from examples. If any one should have seen any potential heresy or treason material was a potential risk anyway. Loyalty has limits.