About how big is a head?

[Moraelin]

I was kinda considering making a helmet next. (No promises, though.) Which brings me to the question: about how big is a human head in the game, please?

[Demeggy]

Apart from making me chuckle at the subject, I'd export a current helmet closest to your design from the game using FOMM and work around that. That or you model and then scale down the helmet, but the former would be way way way easier.