I messed around a bit since the crosshair being off center bothered me too. I was able to make it as centered as possible by changing the "text alignment" from "center" to "west" and then changing the x/ypos to move it back to the center. I checked to make sure that realigning the crosshair actually moved it by adding the default wings again. In short, changing text alignment to west and then moving it over worked for me at 1920x1080.
Before trying west I tried east and it somehow deleted the right wing of the crosshair. Not sure if this is a resolution thing or if that always happens but if changing the alignment to west doesn't work then I'd encourage people to try east.
On top of this, for people who would like the crosshair to be a bit more bold, it is also possible to have multiple konrwing crosshairs aligned to east (not sure if east works though), west, and center creating a more bold crosshair by taking advantage of the fact that they don't align perfectly on top of each other (it still might be a few pixels off center because of the use of the off center-centered text alignment).
If anyone wants I could probably post screenshots of this when I get a chance.