Walking out with that huge duffel bag
Why?
I've read that he didn't want to leave any evidence or DNA behind, so that bag probably contained the tools, weapons, and his coveralls. But why not just leave all of that in the crawl space, rather than risk walking out of a bank with a huge duffel bag. I don't think that's a very "inconspicuous" look.
The diamonds he took were in a pouch small enough to fit in that safe-deposit box. In addition to the Nazi documents, I feel like that's all he really needed to walk out with.