I used to use 2 x 24" at work ... it depends on the space between yourself and the monitor ... sometimes you end up turning your neck alot in that setup, making you form a "curved" or v shape with the 2 monitors. Not sure if people intentionally do this or not, and also not sure what you're supposed to do from an ergonomic standpoint either.
in hindsight to that experience, the 2 x 22" (or 21") comment seems to be most appropriate
I also saw somebody use 3 x 24" with one setup in complete vertical.
Another guy uses 2 x 24" verticals
depending on how good you are with screen real estate, the 40" 4k idea is not a bad idea too
This, I find 20-21 inch fullhd(allows 2 full a4's per monitor) to be the sweet spot, been upto 2 x 24 but found it too big..
or a monster single 4 k...
it really does depend how good you are at window management in an idea would with good window management 1 big screen in best. IMHO
