I don't think you understand what you need to do. The angle the hitch head makes with the truck means nothing. If you tilt the head forward toward the truck, you could take up a chain link. I think you are lifting the back of your truck up too high, especially if the front is down 1". The front suspension may be on the bump stops too. I think you should keep tilting the head forward toward the truck until the front of your truck is at unhitched height or slightly higher. Then move hitch head up or down on the shank until the trailer is level. Keep re-adjusting until it is right. The coupler mount really has no bearing on your setup.
You were already referred to the sticky on setup to read. You need to have a basic understanding of what to do before you start. Good luck.
