As you can see, I have the exact same mount so hopefully this helps you out. This is what I did.
Here's that useless piece that I believe is giving you grief.
That's the piece that is located at the front of the mount.
Here's the base now without it. All I did was just pull it out, no witch craft involved.
In the "up" position it should sit like this
As you can see it's no longer angled upwards
Mind you a lense looking through a lense makes that dot friggin massive but you kind of get the idea...When I aim down the sight its centred for me.
Hope that helps! I found those adjustment screws to be useless truthfully....