copy of an older, barely legible manuscript?

[Jorge_Stolfi]

But instead the writing has an effortless flow to it. The writer wrote whole paragraphs without having to pause or to think what should come next. It doesn't seem to show that the writer was having to lift the pen mid-word or between words in order to consult the older manuscript.

The VMS was definitely written on paper first.  It would be stupid for anyone to write anything directly from head to vellum.

Once it was written on paper, copying it to vellum would be a mechanical boring task that would surely have been given to a scribe.  

That scribe would have to be taught the alphabet, and trained until he could copy it fluently and reliably.  That would take only a few hours.  

That scribe would not need to understand the language or encoding. And there are several clues that he in fact did not.

(There is also evidence that, sometime in the 600 years after the VMS was written,
large parts of the text and figure outlines were restored by carefully retracing them,
because they had faded to almost invisibility.  The scribe who did this restoration
did not know the alphabet, although he may have mostly inferred it as he worked.
But this is still a disputed theory.)

All the best, --stolfi