I keep the autolap on my Garmin 5s, but I switch to the lap pacing per mile vs. overall pacing. With overall pacing it jumps all over the place but by setting it on lap pacing I get a much more accurate reading for my mile splits in terms of pace.
Was able to do 18 today, 10 EZ @ 8:20-8:25 pace, then drop down to 7:33 and hold it for the last 7. The 11th mile was at 7:48 because of a traffic light on E. Broadway and then I transitioned down to MP.
8:36, :32, :25, :25, :26, :28, :12, :19, :14, :31 (10 miles)
7:48, :30, :34, :33, :33, :34, :29, :24 and still had a bit left.
Even if I go out slow this time and stay disciplined, I think with the crowds at WUC the first few miles (loop course) for the 5k and 10k (3 and 6 laps) I may start at 8:10 and work my way down to 7:40 by the 6th lap. Then once it clears to just the half and full runners, I'll set in to 7:33-7:30 pace. I want to have a ton left over at 20 and finish the last 6.2 strong!