I managed to solve the multi GPU problem without cables. You'll need v0.16 or newer to make this work.
1) You need to set up another (fake) screen. Right click on desktop->screen resolution.
2) Click the
Detect button. Unconnected screens will appear.
3) Extend desktop to a VGA connection on the Intel GPU (screen 2 in the image).
4) Drag the 2nd screen to the corner of the primary screen so the mouse boundaries of the primary screen will remain (almost) the same.
5) Click OK/Apply. A reboot is recommended.
6) Open your favorite player and select MadVR or other GPU demanding renderer for to test the setup. You can test further by selecting EVR as renderer, open the control panel for your AMD/Nvidia GPU and override the color settings (e.g. kill the saturation).
Here's a working setup
