Does it work with a 34 inch screen in 21:9 format? I've read that it's 30 inches for best performance. But maybe 4 inches more doesn't make much difference.
I use it on a 27", probably all depends on the distance of the screen where you are sitting. I did a test, at 1 meter it works very well, at 1.30 meters sometimes it doesn't see the face, so probably if with a bigger screen you go further there can be accuracy problems, if you're at 1 meter no worries.