If you are going to be using the club gliders, look at the LX Nano and a good dedicated daylight visible Android phone(I use a Sony Xperia Z3)to install XCSoar or Top Hat on to. Also the LoRa Flarm device would be a good choice for proximity warnings. The Nano and LoRa Flarm are both very portable and you will not need to connect to the gliders electrical system. Total about $650.00 US.

Mike
Could go Nano4 and skip bluetooth to phone. Pluses and minuses to both solutions. What is LoRa Flarm?