As stated above, the black line is generally where you'll want it level. Using the same black line as reference, my saddle is comfortable with about a 3 degree "nose up" position from level. My sit bones hit on the green marks you indicated, but I do tend to move around on the saddle depending on effort and terrain. At the risk of stating the obvious, be sure the floor the bike is sitting on is level when working with fluid levels at the seat.
-Kedosto