As kind of an experiment I did something wild and crazy. I went through FRB race reports from St. George over the past 4 years, and picked posts that had their miles splits for every mile. I then took the average mile spits from 30 data points and used those numbers in my equation to figure out splits in my calculator. It's pretty interesting to compare the results from real life data points to those based primarily on non-human factors like gradient. On average it looks like most people go out much faster than they should, run Veyo hill right about where they should and then crash around mile 18 - 20. This raises the age old question, is it better to go out fast and just try and hold the crash as long as possible, or is it better to go out slow and run a consistant pace.
http://dl.dropbox.com/u/2823097/FRB%20St.%20George%20Pace%20Calc.xlsLast one, I promise.
I did a comparison of 4 different methods for calculating per mile pacing in St. George. The first one is from a Pace Calculator I found online, the second one is from the data I pulled from actual FRB bloggers marathon times, the third one is strictly based on the slope or average gradient of the course per mile, and the last basically uses Sasha's course tool. Very interesting to compare the 4 different methods.
http://dl.dropbox.com/u/2823097/Pace%20Calc%20Comparison.xlsx