I would strongly advise you not to attach a selfie stick to your motorbike! It is far too unsafe and the selfie stick would hardly last long enough, especially since it is extendable. In addition, I think it is very questionable in terms of road safety and you would probably not be able to pass any police officers.

I would recommend the motorbike set, the extensions are fixed and not so long: Insta360 One R Motorbike Bundle (Head / Helmet Mount, Mounts, One R)

Personally, I would recommend the One X2, it has the best price/performance ratio in my opinion.

As I no longer ride a motorbike, I am unfortunately unable to answer these questions.