I want to add my experience about SLI + WMR (Dell visor). VorpX SLI does not work with the driver itself (only 1 GPU is loaded at 99%, GPU 2 is idle). But in vorpX Desktop Viewer mode, SLI works, and more specifically vorpX Desktop Viewer + ReShade with Depth3D (or Super depth3d) (SBS) + SLI. Desktop Viewer + TriDef 3D Ignition (SBS) + SLI also works, but not very correctly, there are constant jerks (lags). SLI also works great with the Virtual Desktop program, supports the same options as described above, and is also buggy with TriDef 3D Ignition.
So the most optimal SLI mode is vorpX Desktop Viewer + ReShade with Depth3D (or Super depth3d) (SBS) + SLI filter, or Virtual Desktop + ReShade with Depth3D (or Super depth3d) (SBS) + SLI.
That is why still can not make a VorpX driver that supports SLI? This is a question for VorpX developers, because the software for WMR headset + SteamVR, SLI fully supports.