This may have been posted at the ol stomping ground, and I'll be damned if I can recall if it has or hasn't. Anyway found this link and thorught how cool. Give it a try and figure out what your speakers are getting with the current gauge wire your using.
http://www.bcae1.com/images/swfs/speakerwireselectorassistant.swf
http://www.bcae1.com/images/swfs/speakerwireselectorassistant.swf