Just back from meeting with one of the engineers at the Drake Hotel to see the blueprints. He led me into a tiny room behind all the electricals.....there were bins full of tubes with plans from all the permutations across the years. It was overwhelming.
Then we found it....the original 1920 blueprints by Marshall and Fox. I can't believe they are just rolled up in the basement. They so need to be donated to the Chicago Historical Society and properly restored. They weren't particularly helpful....but very cool to see.
It took a huge effort, but we finally found something that should be helpful. However, it took so long that I totally forgot that I would need a section too in order to get the floor to floor heights.