FWIW I have finally got to do more testing in 5.1 with nanite, VR without Lumen. I got 6 billion triangles and 80 shadow casting spot lights working in VR at 60fps with virtual shadow maps. it was a very artificial test scene (a single very high poly asset duplicated many times). In a more realistic actual game level I actually had no performance increase with nanite. The non Nanite scene was reporting 4million triangles. That said, not having to deal with LOD and always getting the highest quality meshes with no LOD popping is a big deal. Using virtual shadow maps did not seems in incur too much of a burden either and gave better visual quality (though with nearly all baked lighting, this was not such a big issue).