Hi Sio. Sorry for late reply.
For general tips on flight safety I recommend you reading this article:
For some images about a tethered flight in Australia you can refer to:
In the framework of a festival you do have to get in touch with local Flight Authorities and inquire wether you need permission for a tethered flight event. It might surprise you, there is a lot of existing regulation in most countries about the topic, so it’s convenient to familiarize yourself with it.
If still useful don’t hesitate to get in touch with me: joaquin@aerocene.org. Then we can arrange a call and I can share some experience about keeping aero solar flights on the safe side.