I only have 415 $16 and $27 turbos under my belt, but FWIW:

10/20 16.6% 15BB/100
15/30 17.2% 7
25/50 18.2% 1
50/100 18.0% 3
75/150 21.9% 3
100/200 28.7% 3

My ROI over these SNGs is 20.3%.