Interesting.
Any source?
I'm not sure if the tempo should be 68, as it is not valid at the traditional Maelzel scale. A tempo of 69 might be better. Yes, I know that with modern digital metronomes, any tempo is possible (consider Stockhausen's 83.5, for example).
Interestingly, Prokofiev notated the English horn in alto clef—not because he wanted to change history, but because he thought it looked better! However, this was only in the score, and he orchestrated everything in C.
This I wouldn't recommend. For other instruments, you can do it, but on the other side you have to be consequent, which is more difficult.
Dorico? Wow, congratulations!