Hi Christoph,
I have not seen bluetooth adaptors for KX series, but are some advertised for ft817 series, I don’t know but would think they are readily adaptable to kx. One matter to be aware of is the dc voltage that is usually provided to the standard kx series microphone as bias for the electret element in the mike. This voltage is configurable in the kx radio to be on or off, depending on the type of element in the mike.
In general I have not been attracted to using bluetooth for mike and headphones. I have always used cables, with no extra RF floating around the radio and my head. However right next to me is my mobile phone with bluetooth enabled. Every extra bit of RF around the radio can cause issues and with my KX3 I have noticed the high gain audio stages can be very susceptible to the 3G/4G signals from the phone, which creates some unpleasant noises in the headphones, so I try to keep the phone away from the radio or any cables leading to the radio.
The other issue is the battery required in the bluetooth enabled headphones and microphone. They don’t last forever so they are yet another battery to be recharged prior to activating. If they are your only headphones or microphone you are dependent on them for the operation of your radio. Ie. another point of possible failure, which we try to minimise.
As for preparations, I think the best advice is to activate in the company of other experienced SOTA activators. We all learn something from others and in any case, activating in groups is safer and more fun.
Hope this helps… 73 Andrew VK1DA/VK2UH