Make full use of your drop bags, and put anything you think you might want in them. Have plenty of spare socks. If your feet get wet and start to get in a bad way, a fresh pair of socks can really make a difference. The easiest way to keep your kit dry, is to put it all in sealable sandwich bags. You also want a decent head torch.
Striking on the forefoot tends to counter overpronation, but it is not a hard and fast rule. You do get a forefoot striker who rolls over hard from time to time. Most shoes are designed round heel strikers, so we often see a lot of technology going into the heel, and not much going on up front. There are exceptions of course.
Don’t worry Martin, most people take a few hours longer to do NDW100 than TP100. They are different kinds of animals. Furthermore, even experienced runners can end up close to the cut-offs in a 100, if they have a bad day.
I did this event in the inaugural year. Centurion are very good at organising 100 mile events, and I doubt that they will be found wanting on this front. The first half of the course is mainly paved, and is better handled with road shoes. The second half is mainly mud, and better handled with trail shoes, especially if it rains before the event. You want to take not of the weather in the days leading up to the race, to inform your footwear choice. Navigation is easy for the most part. Just don’t fall in the river. The night section of this race has a hypnotic quality to it. The cries of water birds, and other wildlife related sounds, form a veritable symphony. The flat profile of the course can be an aggravating factor, because you keep using the same muscles, but it is a fast course.