But the sun itself is at a very,VERY low position. Don't think you/I want a pretty small walls with a big skybox.
I'm basically using
this skybox.
Even when you have a low sun it should be possible to have a map well lit. If the sun is too low dont use that as an excuse, fix it by making the sun be a bit higher or compensate it with artificial lights.
Dark areas in most cases dont do well. They make team identification harder, and often benefit classes that dont want to be spotted fast (spy, sniper, medic, pyro), and especialy when too dark these classes can cause ninja wins or frustrating deaths.
If you realy want the sun to be low, add lights to make the map itself brigher. For an example just look at
http://wiki.teamfortress.com/wiki/File:Pipeline02.jpg
For a map at night its a well lit zone.
Even
my own map and using
earkhams assets it has a low sun position (-30), but its still a quite bright map because i add light at every place that was recieving shadows.