My 20 yd. pin is as high as it will go and still hits too high, what can I do to correct this?

Check your nock point. Depending on how it' s set up, it may be at the wrong height and be causing the problem. Also could you move the entire sight up (where it mounts on the riser)?

Additionally your rest may be too high.

Ideally when the arrow is on the rest, the center of the shaft should be at the same height as the center of the berger button. Move your nock point accordingly.