To answer my own question, the answer is dgvoodo2. dgvoodo2 is how you get this working. Follow their instructions for installing it in the game directory. It does work with vorpX, even with the weird engine. Some tinkering around might be required. I had “Do not optimize game settings” and “Run vorpX control as administrator” switched on when I got it working, but I don’t know if that’s required. Try without these options first if you want!
– nightscout01