Newbie 101 - 1) Just stay clear of displacement until you are comfortable with VR, use bumps for now. 2) If you download vrmats from places other than the Chaos site, I would be very careful as these may have displacement, odd settings, high subdiv values that will slow you renders down, etc. Learn to make VR materials from scratch to fully understand what does what. Chaos has some great tuts on YouTube.