What format, size, etc. does QGC and MP require?

I’m about to conduct my first Survey & Mapping operation. My hexacopter uses QGC on my Herelink. I use Mission Planner for my autonomous flights. I will be using either my Phantom or Mav 2 Pro to capture ground at 325 - 400ft AGL. The finished poster will be in color. I especially want to ensure electrical wires and dangerous obstacles can be seen with ease. I plan to pay close attention to the time of day I will be shooting to avoid strong shadows. Sooo…Since I will be blowing up the finished map, which format and size and etc. should I use?