I know I'm late to the party, but man that helmet is incredible. I've been trying to kitbash a hybrid 3/Reach helmet exactly like yours for almost a year out of Reach models and you go and do it in your opening shot! It's based on the version in the CEA terminal cutscenes, isn't it?
I don't suppose you'd be willing to share the STL file, or maybe a pepakura for it? I'm in the process of planning a Package/Infinite/Reach hybrid suit and that helmet is the missing piece of the puzzle.