Your tow vehicle will always go down when the trailer is attached because of the added weight of approximately 1000 pounds. The thing that you want is to not let the tongue weight applied to the very rear of the tow vehicle to lift the front of the vehicle, which will reduce stearing and stopping traction.
I like to measure the height of the front of the vehicle before the trailer is attached, then after it is attached, tighten the bars until the height of the front is returned to where it was before the tongue load was put on the TV.
This is what I like when towing with a truck. A sedan would be different....you would want the front of a sedan to go down the same amount as the rear went down, so the bars would have to be adjusted tighter.