I hate to say it, but the trail and error way is about the best way to go at this. I don't know how many time I would get this killer angle and only to find the camera halfway in a wall. Another way I do this is to get the peolpe posed and lit first. Keeping in mind the dimentios of the room they will be in. then bring in the building, then adjustfrom there. One thing I found to help is ot turn the ground shadow off that way you see better when the body parts start going into the floor.