I'm another software engineer who also plays the horn. I'm trying to help with horn parts, particularly those which are difficult to play in the original notation.
Brahms, Symphony No. 4, 1st Movement, Horns 3 & 4: there are some very tricky fast bits, which (as I know from personal experience) are extremely difficult to play in the original notation for horn in C. In my youth, I went for a try-out to a very nice local orchestra, and they gave my the 3rd horn part to sight-read - resulting in a complete nightmare of missed entries and wrong notes as I struggled with the accidentals in the first movement. Needless to say, I didn't get the spot. Hopefully future horn players will have more luck with the part in F.