Foursquare attic finishing

Does anyone out there have experience turning the attic of an American Foursquare into a master suite? My home is a 1928 2000 sq ft home. The attic is a walk-up accessed by a door in the upstairs hallway. It's the typical pyramid shaped space found in foursquares. I am uncertain whether there is enough space since on all sides the vertical space is diminished by the roof sloping down. Looking for advice on how to determine whether I have enough space to make it work without losing the integrity of the architecture.