I'm considering purchasing the nadir adapter even though it's pretty expensive to get it here in France.

I'm wondering about something: looking at how it mounts, it doesn't seem that it would require changing the camera position settings on either the lower or vertical rail, but I've read a quick test somewhere which pretended that the top rail settings have to be changed. This doesn't seem logical to me as I don't see why the higher position would demand a setting change, as the camera is still rotating around the same point anyway.

Can anyone confirm?