What can be ascertained from Shakespeare and De Vere writing samples?
That there are no Shakespeare writing samples. The only example
of his penmanship we have is his signature on several documents. As
with deVere, his signature changes every time. This does not
suggest that they were the same person, only that people back then
did not develop a single consistent signature or a single
consistent spelling of their name.
Basically, writing samples do not tell us anything about
Shakespeare or Oxford for that matter.