Duster,
Sorry for my slow response.
A "first person" account of Bob Harris' world record flight is contained in the January 25, 1987 daily bulletin of the 20th World Gliding Championships in Benalla, Australia. A summary of the weather conditions during the record flight, by Doug Armstrong, is contained in the same edition.
That article may be hard to come by. If someone would like a copy they can email me (first initial last name at cox.net).
I can tell you that the WGC version is much the same as the Soaring Magazine article you mentioned (Pat Valdata, Oct'88). The only difference I see is that the WGC version explains the perceived problem he had with one of his oxygen systems.
I said his Twin Astir was in the National Air and Space Museum. That's wrong! The Twin Astir was used for his earlier two-place record attempts. The world record was set in a Grob G-102 std III, a single-place Astir, and that is of course, that plane hanging in the Air & Space Museum.
Mike Koerner