I have the support only normal attached to the head without a helmet as a kind of headband - one feels a slight pressure, one is sensitive I can well imagine that one quickly gets a headache, especially in the area where the mounting plate to the head. I feel the pressure as said light - it is not particularly pleasant, but it's personal for me to endure, and the videos that are produced during scooters / cycling or walking really awesome.
It does not explain the instructions with pictures quickly as you can screw together the items.
I use the part with a Sony AZR1. The other parts (noose around the camera where to connect, adhesive hook for the helmet, padding for the helmet) I have not yet used.