Alright, these are from 2021, and I confirmed the course is the same for 2022.
https://www.strava.com/activities/5986622694
https://www.strava.com/activities/5993629600
https://www.strava.com/activities/5987441242/overview
https://www.strava.com/activities/5987577986
https://www.strava.com/activities/5987228703
These five runners are using five different watches. They measure the GPS distance of the race to be an average of 26.57 miles (range of 26.42-26.95). So if I had a specific time goal, I would base the pace off a 26.57 mile GPS finish. For example, let's say I was aiming for a 3:59:59 finish. For 26.22 miles, that's 9:09 min/mile average pace. But for 26.57 miles, that's 9:02 min/mile pace. So you need to plan to be faster than you think for a specific time goal.
These five runners have an average pace vs average GAP difference of 8 seconds (range of 5-17 seconds). So this course is 8 seconds per mile harder than a flat course. Over the course of 26.57 miles, that makes this course 212 seconds (3.5 minutes) harder (at least!). So going back to our theoretical sub-4 runner's goal. They would need to run a 9:02 min/mile pace (based on 26.57 miles), but be capable of running an 8:54 min/mile marathon tempo pace on a flat course. So what was once a 9:09 min/mile pace is now 15 sec/mile faster based on actual fitness level.
Next, I would look at each individual split. The goal is a 9:02 min/mile (for our sub-4 runner), but running 9:02 min/mile pace for every mile split is not the best strategy. It's better to take into account the elevation changes in each individual mile. So I go through and calculate the GAP difference of each individual mile.
View attachment 676867
The grey is the miles. Each of the white columns represent the five runners. The values within the white columns represent the individual's GAP difference split for each mile. The green column is the average seconds difference (or impact of hills). The purple column would be the goal splits for someone aiming for a sub-4 marathon using a 26.57 mile GPS finish time. So while their actual average pace will be a 9:02 min/mile based on their GPS, the goal split for Mile 12 is a 9:55 min/mile and goal split for Mile 15 is an 8:38 min/mile.
Hope that helps and let me know if you've got any questions. Admittedly this is one of the hardest road marathons I've seen. It's a very trying course because of its steep uphills but also because of it's rolling nature. Best of luck, and save your energy until at least after mile 18 is done. Things calm down after that.