How quickly did the VMS leave the possession of those who understood it?

[oaken]

On a few of those long-range travelers would have bothered to write about their experiences.

Yes, it certainly could be that one of those few travelers outside of europe was involved in the vms. Although that might be more motivated if there was a clearer link to somewhere like al-andalus, where cross cultural contact was/had been more common (e.g. christian nobility fighting as mercenaries in the Islamic world) , or if there was anything in the vms that is impossible to explain in a central european context, which I am not yet convinced of. There are surviving later documents from early contact between europeans and the peoples of the americas of course, and they don't look anything like vms, and no amount of redaction could render them to. But I don't discount the idea.