Revised scan done with Litchi (which doesn't natively support "mapping"). To get the proper overlap coverage, the flight plan was initially drafted in DJI Terra with a standard grid pattern. This let me derive the number of waypoints and I just reproduced the same pattern in Litchi using "waypoints" mode. Altitude 115 AGL. Speed 7fps. Gimbal -75. Flight time approx 15min (2.5 batts).
Phantom 4 Pro 2.0 using the legacy smart controller, which is why I cannot use Pix4D or Drone Deploy =/.