I knew somebody would mention Britten. Absolutely "very high strung", as was Elgar. They were excellent conductors.
Thinking of Bax, I tricked myself into saying that!
There seem plenty of "high-strung" individuals that could not conduct (Rubbra, Klami, Sibelius, Shostakovich) and those who could conduct quite well (Bernstein, certainly Arnold, Bantock, Walton, the list is endless).
So, on hindsight "high-strungedness" seems irrelevant here.
Rubbra conducted the first performance of his Symphony No.4 in wartime in his army uniform ;D (and with the very reluctant permission of the Army ::))
Sibelius did conduct some of his earlier compositions did he not ???
