I use a 6" drop/rise receiver for mine. Worked out perfectly. My tow bar tabs are on my bumper, which raises the tow bar higher than if you were to use a baseplate. However, I used a baseplate on my last two JKs, and much prefer this method.
I think most tow bar manufacturers suggest that the bar is sloped down towards towed vehicle (Jeep).
Here is what mine looks like: