your probability for the majority being overturned seems vastly too high to me, we tend to remember the instances where the majority was overturned, but across all fields on all subjects over the course of science they must represent a tiny minority of cases. It is clearly difficult to come up with specific numbers but personally, given the option of betting for or against a scientific consensuses given no other information, I suspect I would guess something on the order of 10^-4 to 10^-5, not 10^-3.