I also own the KEM and like some others do not like the steep tilt.
Never used it without propping it up long enough to cause discomfort, but it feels quite awkward.
I had a spare sheet of 6mm Vibram rubber and cut a few strips to prop up the rear of the mouse, making it much more comfortable to use, while preventing it from sliding around.
It would also work to find some type of rubber wedge.