You can fix a string in the little hole on the top of the wedge, put some glue between wedge and body and then you can pull the string until you are happy with the alingment of the bed. A sheet of paper or something else, of which you know the thickness, should be very helpfull.

(A sheet of paper has the thickness of 0.1mm)

With that you can probe the bed on diffrent points until you found a point, where you need to raise this explicit spot a little bit.

Here a video of the working principle of my design.