Well, it took me a weekend at home to convert this scene, something like 16h maybe… Probably half of that time was just to bring the meshes from 3DS to UE4 what includes attaching little models into the same mesh (eg. those books, I like to attach a bunch of them so it’s easier to manage it and also faster to map). A lot of the evermotion models are formed by tinny individual meshes grouped into a single object in 3DS, so there is also the pain of attaching those parts into a single mesh. For the mapping I’m also going for the lazy mode, “flatten by angle” for everything in the scene :p. Then, if something gets too many lightmap artifacts, I return to 3DS to adjust the unwrap manually.
There is only one mesh in that scene with a 2048 res lightmap and that is the floor. It’s not enough yet, It’s a single mesh and I need to subdivide that into three pieces at least to get better lightmap resolution without exploding my rig’s RAM 
I don’t use the same lightmap res for everything. I try to maintain everything in the scene with the same lightmap density. To give you an idea, the furniture gets 128-512 and walls get 512-1024.