Any one knows how to get dcs run right without paraller projections ?
PP off = clouds render left / right eye unsynced (visible in left / not in right etc) and using VR zoom makes cross eye effect.
PP on = no problems but performance gets hit
Performance is an ongoing issue with DCS - they posted a while ago to bring VR Optimisations, but they have not made it into the game as of today. 
You can just try with FFR, SuperSampling and Resolution and the smothing to get somewhere where it is playable - but it stays very demanding (mostly since it does not utilise multi CPU or GPU’s very good).