No motion controller or Vive tracker position tracking in Unreal Engine without HMD?

I have steamvr setup for requireHmd false to remove the HMD requirement. I’ve verified steamvr is tracking without the HMD. Unreal Engine is not tracking the motion controller or the Vive tracker. Does anyone have tracking working in Unreal without a headset attached?

I’m trying another route Run SteamVR without HMD? :: SteamVR Developer Hardware General Discussions

Basically don’t use requirehmd false, and setup this null driver which looks like a headset without one being plugged in. This might get unreal to continue tracking other devices.