learsfool:
Welcome to the thread and congratulations on being a professional on what is, assuredly, the most "unpredictable" of instruments.
My favorite horn piece has always been the Schumann Konzertstuck and recently found a recording with natural horns by Gardiner and the ORR. Lots of power, needed for the natural horns that seem better at bombast than lyricism.
Have also recently explored the Mozart/Karajan/Brain recording you mention and it is astonishingly good for the 50s. A tragedy that he died in a car accident at the height of his considerable fame.
Keep us abreast of the horn recordings these days and, once again, WELCOME!