I am not convinced by the provenance history of the VMS

[Jorge_Stolfi]

So it is theoretically possible that a forger in the mid-1600s created a manuscript that pretended to be the work of some forgotten genius who invented the instrument in the 1400s.

I didn't realize you were open to a post-1420 origin by hundreds of years, and to a possibility of forgery of optical devices.

I was speaking generically there, not about the VMS.  

As you know, I am now convinced that the VMS is not a forgery but a honest transcription of a Chinese classic.  This implies that it was written before the 1600s, because after that the Jesuits would have got translations or pinyin-like transcriptons.  And if it is not a forgery, then the C14 dates for the vellum are string evidence for a mid-1400s date.

But, even so, I give significant probability to BL MS 408  not being Baresch's book, and to its history before 1912 having nothing to do with the "consensus" version.  I think it is quite possible that MS 408 got associated with Marci's letter either by mistake, or intentionally by Wilfrid -- either because he was unable to get the real Baresch book, or because he got it but found that it would never pass for a Bacon Original.

... many who hold that the 1420 Genuine European Cipher Herbal paradigm is the correct one, are nonetheless open to all these: ... that it probably has nothing to do with Bacon

I don't think anyone believes that by now.  Not an original in his own hand, not even a later copy of one.

that Voynich clearly knew it was not by Bacon

I gather that he found some "experts" who supported that view, and choose to go by them.  But any real experts on Bacon's works should have told him "no way".

that it may have been inked hundreds of years past the C14 dating...

I think that the poor quality of the vellum gives a bit of support for this theory, even if the book is not an intentional forgery.   If the vellum was fine, we would assume that it was bought for the purpose and came from a trader's stock that was quickly renewed.  But the poor quality of the material and the obviously unskilled Scribe say that the Author was financially stressed.  Then, instead of buying fresh vellum, he may have fetched the box of rejected sheets that his great-grandpa left in the attic, and begged friends and local monks to do the same; and/or he may have removed blank bifolios from some old "student-quality" books that he happened to have.  Or cut out folios from larger books and folded them as bifolios. 

All the best, --stolfi