Tail sitter flight controller recommendation

ArduPlane
1

I am building a tail sitter similar to CAIPIRINHA and I have few basic questions.

  1. Can I use any PixHawk FC for this build? I am planning to use Pixhawk 2.8.
  2. Is there a frame configuration for tail sitter that uses rudder as well?
  3. What is the optimum motor-to-motor distance required?
  4. On the documentation pages, flight modes are not well defined for tail sitter. Can someone point me to a document specific to tail sitter setup using Qgroundcontrol OR Mission Planner?

Thanks