which exact file did you use for the helmet in your first post?
It's been three years since I pepped the helmet you're talking about. I have no recollection of which exact file it was, but the HD model was from flyingsquirrel. You can still find it at the HALO costuming wiki for download. Good luck.
In other news, the cascade of mold failures continues:
This is what was left of the helmet mold after it gave birth to its last casting. It was a sad day, but it gave me a reason to finally go back and fix all of the tiny, annoying details I've found wrong with my helmet model over the years. Stand by for a much-refined version 2.0.