Hi @mnpmilan,
This comment may be a good starting point for your understanding of thruster contribution factors, and this one covers some specifics of the BlueROV1 frame.
From your picture, at a high level your 1/2/3/4 thrusters contribute to vertical, pitch, and roll motion, so should have non-zero factors for those, and your 5/6 contribute to forward and yaw motion. You don’t have any lateral control authority. The actual numbers depend on the mass, volume, and thrust distribution of the vehicle.