about an arms length..Eyesight is pretty good, not perfect though.
The thing i like most about it would be more vertical space for not so frequently used stuff and no bezels.
I would go for option (2) but I think I'm less worried about the vertical height and having separate screens on different data works for me so the bezel isn't critical.
At the cost of bezels you could go for option (2) with the screens rotated to portrait.
I would probably go for the option (2) provided your eyesight is good and the screens close enough to get some benefit from the higher density.