On the longer expedition type trips, like the GC, I’ve become a big fan of bringing a couple of neck, wrist, and booties along. The NRS tutorials are a great way to learn how to replace gaskets yourself, it is really not that hard.
I have seen one neck, and two wrists blow out on winter GC trips, on the two wrists, I was able to just help the guy replace them. I’d had some practice doing one on my own drysuite back at my house, and they turned out almost as good as factory.
If you are at all good at fixing things, just buy the materials and do it yourself, that way, when you get to go on one of those epic trips, you will have the experience to just replace the blown out gasket, and stay dry, warm, and happy the rest of the trip!
So many rivers, so little time...