Hi, that is definetly possible! The voxlization time for the whole scene is 10-20 ms, so when splitting it would work very fast … you could have a look at sparse voxel octrees … I’ll implement them for my GI too, they allow a theroretically unlimited size of the voxel tree, if you combine that with mipmaps, you have a lod system 
If you do everything on the gpu, as I currently do, you won’t have to write the textures to disk, which saves you a lot of time.