General rule: have more vertices and less complex materials. Parallax occlusion is heavy, but I use it in not so complicated scenes, and it’s fine.
There are some additional recommendations for forward shading (‘Normal curvature to roughness’ in materials) and MSAA (use LODs and draw distance, because MSAA doesn’t like vertices overlay in one pixel).
Particle effects with large particles and other large billboards don’t work good in stereo.
Normal maps work fine, unless they simulate very bumpy geometry at large objects.