Here's the issue:
Third floor of my house used to be the roof, a flat roof. House was built in 1885 and a third floor was added around 1920. Apparently they didn't care about the 8" difference over twenty feet.
Normally I would pull the sub-floor and sister joists to get my level floor. However, I am taking back the drywall on the second floor to the joists and using the old sub flooring as a ceiling. A new thread can be started on the aesthetics

. This will achieve a twelve foot ceiling on the second, but takes away my option for leveling the floor on the third. This is all to say, if I sister new lumber, I will see it. As it is now, it is all 130 year old wood and looks nice.
As I said, it is quite a pitch, but the house is relatively small: 18' wide by 25' long. The third also has a pitched roof, so the "floorable" space is only 12' wide. Any creative recommendations/thoughts would be greatly appreciated. Again, there are no structural problems...the floor was meant to slope as it was built as a flat roof building. Thanks in advance.