Just a footnote:
Over the Tom Snyder Show on late night TV, just before he retired, Snyder had some of his favorite past guests ("gave good interviews") to chat for an hour or two, each. The two I remember were Bobby Blake and Merv Griffin -- what an odd couple!
Merv Griffin began to talk about Welles in connection with the subject of being a professional interviewer. He said that Welles was possibly most historically important regular guest on "The Merv Griffin Show," and the best interviewee that he ever had. All Griffin had to do was invite Welles to a studio or to his estate, mention a subject, and away Welles would go. Griffin joked that, unlike many interviews with others, he always had questions left over after a session.
My point is that Griffin claimed, over the years, he had recorded 600 hours of Welles on tape. When Snyder expressed amazement and gave him a certain look of incredulity, Griffin said "come on down" (to some room on the estate which they were evidently both very familiar with), and he would show Snyder. He said, the 600 hours were all stored there, under perfect conditions, for posterity.
Another quest! Where are our pith helmets?