Sensor Position Offset Compensation IMU & GPS

I have a very large rover that will need the IMU_POS1_X moved drastically. I will also have two (2) GPS units. Do I offset the GPS(s) to the virtual position or the actual position? Is the IMU position change factored into the calculation for the GPS?

The rules on ArduPilot are :

  • IMU offset are relative to gravity center
  • GPS offset are relative to IMU