I went outside to take more measurements! The tongue of the trailer is level when the bottom of the coupler is 13" off the ground. The trailer is a tricky thing to measure due to how it was put together and who makes it. Mine is a Continental trailer. For example, the tongue and the planks are on different planes in my case. So, I decide to measure the levelness of the hull of the Spark. The hull is level when the bottom of the coupler is 14.5" off the ground. I was measuring these things because I have been wanting to know how to get the Spark level in order to check the oil. I'm going with the levelness of the hull.
I have a Mazda3, Draw Tite hitch, 2" ball and a 5" rise tow bar. When the trailer is attached to the car, the bottom of the coupler is 15.25" off the ground.