I've started work on cladding the head in 22 gauge steel sheet.
After spraying around the template onto the steel, I cut around the steel with metal scissors. I used gardening gloves to protect my hands from the metal edges, which can be very sharp.
After that, I folded the metal for the horizontal parts by clamping it between pieces of wood, and hammering a block of wood against the fold marks. The picture below is of the front of the nose.
I cut the horizontals about 1/2" to 3/4" wide on either side to make tabs which I can fold over to help with attachment. It's much like doing the same thing in paper or card - just harder work.
Below I've just clamped the sides in place to get an idea of how this is all going to work.
I'm beginning to believe that this might actually work. I'll have to use a fair bit of Bondo (car body filler) to fill the gaps, but it looks doable...