As I know DCS does not provide a way to adjust monitor angle. Major simracing titles enable you to adjust the angle of side monitors, so the image is not distorted. I've tried many ways to adjust this with .lua files in DCS; but there seems to be no way.
And to me, without proper triple screen setup, it is a complete waste of money :)
I have first generation Samsung Odyssey HMD. No other setup comes closer to the immersion it provides during aviation simulation.