On such a long ride, a flat is inevitable, maybe even ten flats. The reality is fixing a tube on the trail is a pain in the ass, so I went with the Nuetech Tubliss system. Yes, tire changes are a bit more involved but for me being able to plug a tire on the trail vs patching a tube is worth it. No need to take the wheel off the bike and pull the tube off all while kneeling, probably in the rain. Instead, leave the wheel on the bike, find the leak and plug it. Yes, I know you can’t plug a side wall, but most of the time I ever got a puncture close to the sidewall it was a pinch flat, and if you tear the sidewall you are screwed anyway.
If I do get into a situation where I can not plug the tire, I carry 4 extra large zip ties which in a pinch can be wrapped on the wheel at its quadrants and you can limp to the next stop. I also carry a 21-inch tube which can get you by in both front and back.