12" viewing distance?! It sounds like you should be spending more at the optometrist and less at Best Buy. I cannot even imagine sitting that close to a screen--don't you have to turn your head just to see both sides of a document?
It's probably more like 18" currently. I don't know, what's your reading distance to a book page? I use FancyZones to dividede the screen into 3 vertical areas (like having 3 monitors). For coding and longer reading periods I use the middle area. But yes, to look at the side areas I have to turn my head or even slide the chair a little. The angle could be better, like I said.
Regarding reading distance: For me the important part is to sit straight and avoid hunching. Choose a combination of distance and screen scaling factor that works for you...
