I believe possible advantage is defined firstly by ball jumps scatter.
I looked some older posts but many attached files were lost.
Here is one with some data and relationship to the rotor speed.
In my files I found some info for Huxley.
Everything above green line is an advantage.
While the highest pick for fast rotor is at -2 pockets, on a slow rotor it is actually the lowest point.
Red line may produce ~60% advantage but it is narrower.
Blue line at +7 pockets and around may be ~30%.
That would be if you can each time predict exact ball drop point. Of course that depends on many factor but making it close 50% of time would be a nice success.