Field of view, (hereinafter FOV) is one of the most important parameters to achieve a fully, almost, perfect immersion feeling. If we make a right choice, and we get used to it, we can measure and precise every corner, apex, distances to the braking spots, rivals, or whatever is on the track with more confidence. You know which my motto is; speed comes with confidence.
I am not going to develop a FOV explanation on this post, but depending on your distance to the screens:
1 screen ~50-70 degrees
3 screens ~90-120 degrees
Here we have a nice videos. RR and iRacing.