https://www.amazon.com/dp/B074K9ZFG2 For screws/nuts that fit GoPros
Area where nut is held is not very tight fitting, and there's not a ton of thickness there but shouldn't be a problem.
I also used VHB tape to affix to helmet.
https://www.amazon.com/dp/B07K4PQG8P
The author marked this model as their own original creation.