I just tore apart a 1965 Volkswagen Beetle with factory foam behind the rear quarter Windows and zero rust. I guess if I can get 50 plus years out of my metal I'll be happy. By the way, R value means nothing in a metal building, you have to seal it up first. Best way is closed cell foam, trust...
Building looks great! Not many people realize how much work goes into a building like this even though you hired out the main building, for instance site prep and all the finishing touches. Looks like you have a nice piece of land.
You can anchor to the wall with wall ties, that's how I'm doing mine. The floor anchors are for forklift accidents, so the uprights won't buckle on impact.