CALCULATE YOUR TIME AT THE VARIOUS CHECK-POINTS ALONG THE RACE ROUTE
Rémi Poisvert's internet site allows you to enter your desired overall time, your pre-determined rest stops, and your 'slow-down' coefficient to give you your hypothetical times at the different check-points along the race route.
A great tool in helping you prepare your race.
Be warned that on race day you should not let yourself get caught up in a psychological trap based on your own previsions: your state of shape and the weather conditions could make your race very different from you what have envisioned.