There is already a wedge design created, I used it and modified it. Props to jrockway

The main changes are, that the wedge is roughly the same angle the Moonlander supports as a maximum. And you can tilt down the thumb cluster, this was something I was not keen on the original design, that it stays straight.

Just mirror the stl and you got yourself 2 pretty stable wedges. What's nice is, that its a more stable feeling in general and you can get rid of the feet if you want, for a cleaner look, of course this is highly subjective