How to select which supernatural to believe?

[Jehanne]

That a human being could, in advance, predict the exact head/tails outcome, in advance, of 100 coin tosses (or, 1000 or 10,000) and have that event ascribed to naturalistic causes is, in my opinion, abjectly absurd.  I see no reason to discuss that further.

That's a very surprising statement coming from an atheist. I completely agree, of course, that there is a threshold of small probabilities beyond which it's no longer reasonable to deny the supernatural cause. Still, a skeptic can find ways to reject your assessment, that a miracle such as predicting 100 consecutive coin tosses may indeed, at least theoretically, have a naturalistic explanation. It's not hard to suggest some far-fetched scenarios : say, some really concealed sleight of hand allowing one to manipulate the outcome of coin tosses, or something similar. And even if such scenarios are not available, the skeptic can still get away with the well-known general objection: they guy correctly predicting 100 consecutive outcomes has a burden of proof, he needs to establish supernatural causation independently. It's clear in this example that there is problem, a big problem, with the level of evidence some atheists suggest to accept that there is a supernatural being. 

I am tempted to say that only a supernatural being can know/detect/understand supernatural causation, it's almost a matter of semantics: by definition of supernatural, it's beyond natural means to investigate it any way. 

I am going to anticipate one common objection to what's above: but God supposedly wants us to know Him? Well, yes, that's why he sent prophets, and made the world in such a way that only through prophets can one know ultimate reality, and not through any other kind of independent investigation.

You're back!! But, yes, I agree with you completely; utterly small probabilities, if specified a priori, would constitute a miracle, and hence, supernatural agency.