I had the same problem, and it was easy to adjust using the knob (not with bare hand, though). Forget about the center marker. When I centered it, it was way too low, and left & right sides didn't match, either.

I ended up using my other car as a reference against the garage door. My neighbors must've thought I was crazy moving cars back and forth late at night. My next house is going to have at least 2 car garage just to make it easy.
Also drove both cars around and mentally marked where the reference headlights were pointing at various objects. It would've been easier going to a local garage/shop, but...