Nickel plated steel sounds about right yes. It was definately not aluminum. Pretty heavy for a header.

The plane is very light and I'm taking care to build it light too, I've hollowed most blocks, omitted some strengthening etc but as long as it's under 8 lbs I'll be happy. But 7,5 lbs seems achievable as it sits right now. I'll try and get the parts on a scale soon and try to add it all up and see. It will be film covered.