Is the 42" a 1080P or a 720 resolution? I like(and use) 27" screens, but they are a lot closer to my face than the C24 will allow(and, if you go with more than 1920x1080 resolution, things are going to get even smaller). My main screen(which IS at a distance the C24 would allow) is a 43" LED TV running at 1920x1080 and I would likely never got back to a smaller EDIT window(but you may have much better eyes than me
). Also, consider stacking screens instead of side by side
maybe a pair of 34" ultra-wide screens?