Over 40, under 3? Determine the pace!

I am 43 years old.  A johnny come lately, I've been attempting to run a sub 3 hour marathon for a couple of years now.  I am making progress although it's been a journey of many dead end paths.  In Chicago, I was very close and feel had I had cooler temps a 1% increase in pace could have been realistic.  That would have allowed me to obtain my goal.  Regardless, the fact remains I didn't do it. Now, my friends who also ran the race chose what they deemed to be the "correct" pace to run the race. Some ran into unexpected difficulties. Some in aticipation, chose to fight another day. Here are our splits for each 5k segment (click on the graph to enlarge):



I started thinking about why we determine our paces in the first place.  The three hour marathon is a lofty goal for many of my running friends.  Some have smashed through this objective while others struggle with me.  Despite our varied talents and fitness, the goal remains one of the most sought after for my group.   Matt Fitzgerald wrote an interesting artical about marathon pacing where he speaks of the difficulty of determining an accurate pace given all the uncertainties of the marathon.  He writes:

"Can we even assume that even pacing is the best marathon pacing strategy? 

The fact that most of the fastest men’s and women’s marathon times ever recorded involved negative splits would seem to be strong evidence that negative splitting, or at least even pacing, is the optimal marathon pacing strategy. One of the world’s top experts on pacing strategies, Ross Tucker, Ph.D., finds this logical irrefutable. “I'm a big believer that there is such a thing as ‘natural selection’ when it comes to performance,” he wrote in an email. “In other words, if the very best athlete runs a negative split, then that is most likely the optimal way [for everyone] to go about it. Because given that hundreds of world-class athletes are racing, time will eventually ensure that the optimal strategy is settled upon. If a positive split were better, I have no doubt that all the great athletes would be going out and doing it, simply because it works.” 

The big problem I have here is the anectdotal evidence does not support even splits for the non-elite athlete.  There are two problems with the supposistion that it's best, first does the non-elite runner really know what the correct pace should be and is the pace for them at which a negative split becomes possible as fast for the entire marathon as the pace they might pick were they to run a positive split?

Fitzgerald continues....

"However, just because even pacing seems to be the optimal pacing strategy for the world’s best runners doesn’t mean it’s automatically the best pacing strategy for you and me. There’s a large and possibly crucial difference in the fitness levels that elite and non-elite runners bring to the marathon event. It’s plausible to me that the more modest a runner’s fitness level is, the more likely it is that he will achieve his fastest time by running somewhat aggressively in the first half and then “hanging on” in the second half. Put another way, it’s plausible to me that the smaller the difference between the most comfortable pace a runner could sustain for 26.2 miles and the fastest pace he could sustain for the same distance, the more likely it is that a slightly positive pacing pattern would produce the best overall result. "

From talking with even our very best runners seems to support this argument.  Do you agree?  Please weigh in on this if you have a moment?