By default, on Cura, the model will be in the 1/100 scale which was enough to have a good result on my ultimaker 2. It can also be printed bigger. Print the building and the roof with 20% infill (maybe less is possible?) with supports at only 5% density (it can be a little bit more for the roof). To make the supports easier to remove, the Z distance can be set to 0.15 mm. Print the curtain wall and the table without any support. The file "Rutonome full" is not meant to be 3d printed