He lived from 1739-1813. This puts him firmly in the Classical period if not the very late Baroque. I'm not familiar with his pieces, however from the time period high Eb's aren't uncommon, and in some compositions and cadenzas were played quite often. Of course since they did not have valves they would have played it on a much shorter instrument.
I'd have to hear the piece to know whether or not that particular brightness of the horn is needed. My guess is that if it adds to the piece, then play it. It's only an Eb :P Sometimes though it is better to be safe than sorry, and to be safe I would probably just give high Bb horns to some trumpet players if I was scoring everything out for a performance. You'll get a ultra bright sound though, and as far as I think it's not copping out or anything if you wanted to do that. Of course if push came to shove and I had to play it, or if I had to give the part to someone and didn't want to make any enemies I'd shift it down an octave definately. -William _______________________________________________ post: [EMAIL PROTECTED] set your options at http://music.memphis.edu/mailman/options/horn/archive%40jab.org