[mhays]

The distance from the public core (elevators, hallways) to the outer facade is a huge variable. Modern office buildings tend to be thick, with large floorplates. Most residential rooms want windows -- living rooms want them, enclosed bedrooms need them by code, etc. If your depths are 50', that's difficult. Depths of 30' will pencil much better for residential use, while also being less desirable from an office perspective.