Wear the Dominators or get another pair of Sidis. The lower end Sidi Bullet 2 model is fine as well. That is what I used on the TA. I carried a pair of Crocs to give the feet a break from bikes shoes when in camp.
My daughter used a new pair of Shimano MT somethings and they barely made the TA. They were shot at the end and she complained about them all the way across the US. In fairness I will say that the complaint was mostly the fit though. She bought some Sidi Bullets when she got home and is much happier with them.