OP, Chris Carmichael wrote a decent book on nutrition for athletes called, _Food for Fitness_, you should check it out (It contains a lot of annoying references to PowerBar, but otherwise it's pretty good).
Here's a table that is probably closer to what you want...but you're asking for trouble (BIG trouble) by making changes on race day.
http://www.trainright.com/articles.asp?uid=2385