Helmet size, and scaling!

I built my first helmet, and I scaled it to 280 mm. Witch after I was done found out it was to big ( Pictures Below ). I'm fine restarting but evertime I print at a smaller scale it looks the same. Anybody out ther that I can give my domensions to and you scale for me? Also i hate the auto scaling for width and depth, really throws me off.

just ignore those other two measurments, are you measuring from the bottom of your chin to the top of your head in a strait line? for my head its about 9 inches 229mm but i scaled it to 9.5 inches 241mm just to give a little extra room for rondo and padding
so try measuring like that then add like half an inch.

241? That's way too small. mine is 267 and I have a small head. judging by your helmet I think going to 270-275 would be good. I had to rebuild my helmet four times before it fit.