Question re: helmet templates and cross bracing

Hello all. I just starting my own cardboard helmet and I'm using Wizard's great templates. I've noticed a few people using some sort of cross brace as they design the top portion of the helmet, but I'm having trouble making one.

Is this done by scratch or is there a template a failed to download for this cross brace?

You'll find it in the templates Wizard of flight posted up, only you'll see them as solid sections that go on before you attept the dome. They're there to add support whilst you're doing the dome and when you come to cover it in bondo or joint compound or whatever filler you choose. I trimmed mine once that was done and cut a circular section from the dome base or you won't be able to put it on your head. You shoulod find them on pages 5 and 6