Recipe for SphereBota

I wanted to have SphereBota - something like plotter allowing for painting the spherical objects (eggs, balls, baubles).
It was something like this:

Helmet camera mount

I bought Mobius ActiveCam cemara. Quite good device, but unfortunetly mount is not enought good for helmet curvature.
I thought about making mount on 3D printer, but to do this i need model of helmet.
To do this job I make simple device: spherometer, which allows me to mensure radius of helmet curvature. My project for printing is ready to print and avaliable here