Hello,
I've found a number of various "recommended" shadow tweaks for skyrimpref.ini; all listing different values for how to improve shadows.
The thing is, I have no idea what most of the settings even do aside from resolution and distance... I am looking for a balance of performance versus quality in terms of shadows. Two examples below.
http://itcprosolutions.com/skyrimguides/tweak_guide.htm
http://www.rcrncommunity.com/five-quick-skyrim-tweaks-you-may-not-know