What is the Size of Darth Vader's Helmet????

[Uai]

I'm making my first replica with a pepakura file of the Darth Vader's Helmet.
I'M A BEGGINER IN THIS KIND OF MODELING.
The size in the Pepakura Designer is 300m of Height.
I would like to know a good size to make my helmet.
If you have a Darth Vader's Helmet, please, could you tell me the size???

SORRY FOR MY ENGLISH and SORRY because I'm a begginer and I don't know much.

Thanks a lot.

Uai
[from Brazil]

 

[Uai]

Sorry, I forgot....
I guess 300 mm height is to small.