Any advice appreciated with Christmas classic "Santa Claus conquers the Martians"

For years the B-movie "Santa Claus conquers the Martians" has been a part of my holiday, and this year I thought I would try something extra fun by building a Martian costume. After watching the movie more times then I care to mention and examining screen captures I am stumped as to how to start on a helmet. I think I can identify many of the parts but the helmet itself is a mystery, any thoughts?

There some great screen shots here : 2011 December « Gütenfilm.

I always thought the helmets were modified football helmets worn backwards.
Would explain the funky look.

The rayguns were Whammo Air Blasters: http://www.therpf.com/f9/santa-claus-conquers-martians-found-prop-36685/

The little Martian toy seen at thebeginning was a customized Captain Action figure, and would make a neat prop display (as well as help working out the costume & helmet details to scale up later!).

C.