Hey there Flip. I have made abgates old and new version of the hayabusa helm. I know the sticked topic about scaling is a little weird, but like (nul).exe said it can give you some good tips. I will help you out only because i had such a hard time with it myself. For abgates first hayabusa i made it way to small, but I don’t remember what I scaled it to exactly, but that doesn’t really matter since his second one is much better. For Abgates second 2 piece hayabusa helm i scaled it to 28cm and it was way to big. I was able to fit my hand in it with me, so i would suggest trying 26cm. Hey and i would stop double posting before you get in trouble...thats my tip for ya.
As you can see in my picture the 2 part helm is way to big
http://s706.photobucket.com/albums/ww62/stevensickler/?albumview=slideshow