Thanks for the detailed advice. That's very useful. So in effect the main issues seem to be weight / sharp edges if at all. I will check that out with my CCI. The helmets on your website look great.
I was thinking about buying a motorbike open face helmet and goggles and use them for skydiving in the UK. The motorbike equipment seems cheaper and comes in a greater variety.
I am not planning to fix a camera or to use an audible.
Does anybody have any experience / safety issues / tips with this?