Thanks for the explanations and most interesting estimation formula!
At the risk of being wrong, i tend to remember when i trial factored Wagstaff ( (2^n + 1) / 3 ) that odds dramatic low that at a reasonable large domain, less exponents would be left than in a similar domain, given the same sieve depth.
Yet quite possible that with the much tougher sieving that's needed for Riesel, that sieve depths, though impossible to do at home that deep, still aren't deep enough for statistical logics to become reality.
