I have to correct my numbers since I goofed up the expected score for max rewards.
Also I have to adjusted the ravens I encountered this weekend (Hall of Guardians rework):
After the 1st raven (~room 10) every ~37.5 rooms I encountered a raven (~4.16 floors).
The expected room varies around +/- 1.
1st at floor ~20 - 30 (Rooms done so far: ~9.5)
2nd at floor ~60 (Rooms done so far: ~47)
3rd at floor ~100 (Rooms done so far: ~85.5)
4th at floor 140 (Rooms done so far: ~122)
5th at floor 180 (Rooms done so far: 159)
6th at floor 230 (Rooms done so far: 202)
Tier 0 Floor 200:
~91k short of max reward
Tier 1 Floor 210:
~51k short of max reward
Tier 2 Floor 220:
~10k short of max reward
Conclusion:
Tier 2 might be enough in some cases. Tier 3 should always be enough.
Using the list from @TimeKnight:
Hall of Guardians is below 3.9 multiplier
Edit:
Tier 3 Floor 270:
