That's a philosophy I've adopted too. There is always more that could have been done to prepare for a race - by a mythical person who stayed perfectly healthy and had nothing to do other than prepare for that race. The rest of us can only get "ready as we can be" - and most people who finish ultras are in the same boat.
It is all in the mind...you are so ready!
And you have an iron stomach in the last few years... You've got this one.