Indeed positioning WMR desktop in the VR cokcpit is a bit of trouble. However, not as much trouble as installing my real world kneeboard 😉

My only problem is that while using pilot2atc the in-game taxi helper stop showing due to myself disabling the in-game ATC. There again I cannot see the taxi way on pilot2atc in vr and need to glimpse a bit out of the headset. 

There is a button in P2ATC displaying the assigned taxi route on the map. Located on the right side of the map (vertical strip of butons - Taxi is one of them).