I have played almost all awake hours these past 5 days, still no luck.
Here are a few ideas to improve millionaire manor.
1 add more lines
2 add a 4th row
3 allow portraits to be found more than once
4 if 3 or more detectors come during bonus, bonus continues
5 require 3 detectors to end bonus
6 2 portraits unveil ghost
7 if 4 or more detectors trigger bonus, need 3 or more to end bonus
8 bonus spins are free
9 portraits add up between spins
Obviously i do not suggest all ideas be implemented, but they are a start.