How fast could a scribe write a Voynich like text?

[dexdex]

It's all extremely speculative.

If they copied, were they necessarily in a hurry? Or did they attend to other obligations in between? How experienced were they?
If they generated the text through some mechanical means (dice, cards, grids...), how long did this take them and how much did they hurry? If we calculated how quickly it could be done, then why should we assume that it actually was done that quickly? Why not ten times slower?
If they generated the text through some mental process, how much effort did this take? How long did they think before writing down each word or sentence? How many breaks did they take?
How much time did they have in a day to spend on this project?

These are all things we simply don't know. I guess one could calculate a minimally required amount of time for each scenario, but even then we don't know how fast the race was actually run.

Of course, but if writing an enciphered text would take three years but writing gibberish ala gaskell & bowern would take a month (these are just random numbers for the sake of illustration), the effort is easier to justify for the second case and the balance of probability changes. 

Also, the text was apparently written with ink from similar batches, which could be taken to imply a quick turnaround.

For that reason, some inkling WHAT the speed would really be in each case is useful.