I haven't looked into the relationship with the firmament, but I do know that Red Shift is nonsense. It was debunked by a top scientist who was then blackballed in the scientific community.
It's catching on more and more now. Just do a Google search on "red shift debunked". There are various alternative theories about what it means, but no certainty, and it's pretty clearly understood that red shift does not prove anything about an "expanding universe".