Are the 1430s the most likely date range for the Zodiac drawings?

[Mark Knowles]

When discussing expert opinion it feels like some people are using the term as a black box. So they are saying "this" is expert opinion and therefore unquestionable truth. However in this case, in particular, expert opinion is alluded to, but not clearly quoted. I think expert opinion when it exists needs to be quoted in detail. It also greatly helps if the expert can explain the basis of evidence etc. that they formed that opinion on, so that one can understand the underlying reasoning behind the opinion.

Here as far as I can tell the only expert opinion we have to rely on is a statement that Robert Wieck said something about the Voynich clothing dating from the 1420s.