OK, the red taped off area is the internal measurements of the structure and the green taped off area is the external measurements (so could be used for the rooftop hex layout).
The second picture has those two black shadow spaces to represent where an elevator shaft could be cut in. Should I go for four wide instead of two wide? Or does that take up too much space?
Here's the rooftop representation. You basically get five extra hexes (though some of those would have to be taken up by a rooftop access area for the elevator. There's enough wiggle room up there for quite a few partial hexes if that's appealing.
