How Much Protection did Helmets Provide

[markusaurelius]

I agree that different soldiers would have worn different amounts of padding, from just a thin layer of cloth inside their helmet to a thick felt cap, but I'd be surprised if it was ever as thick as an inch.

I agree. If you look at the size of the originals (unless the heads were considerably smaller) there was no way an extra huge layer of padding could be worn all around. A lot of the helmet clearly had room to spare at the top, so having some sort of pad at the top of the helmet seems very likely.