Sensors don't argue with each other. One side doesn't argue with the other side does it? Depends on how wide boom is and how uneven ground is if they would make a difference in you situation. They work by whichever sensor is closest to the ground as being the one that keeps it at the minimum you have it set for. I have seen situations on mine where one sensor is at minimum and the second 2-3 feet higher.  Speed will be determined on how fast the Hagie can lift the boom an how low you are spraying. Just takes common sense. If Hagie drops in a hole or ravine and booms are 20 inches off ground probably won't lift fast enough. In my experience the Norac send signals faster then my hydraulics are so just have to watch for extreme situations. That being said it is a nice system and works very well if set correct.