Ah, excellent! Some scientific evidence for my preferred setup: 2 x 9:16 27" monitors, one in front and one to the side. (Plus another display, of no specific kind. Laptop, landscape monitor, etc.)

I sit with my eyes about 1 metre from the screen, and a 27" portrait display is approx 33 cm wide. So I think that's tan(FOV/2) = 16.5/100 = 0.165; FOV/2 = atan 0.165; FOV/2 = 9.37 degrees; FOV = 2*9.37 = 18.74 degrees. It's almost perfect!

(But even if my maths is wrong: this has proven a good setup for me, which I've used for many years now, and I recommend it to anybody thinking of experimenting with their desk setup. Many monitors come with a stand that allows rotation, so it's not necessarily difficult to try. If you don't like it, you can always switch back.)