  We introduce two approaches to analyses of Borel sum rules. In the first
method, we take the Borel mass M2 to infinity. Here, the sum rules become very
sensitive to the chosen threshold s0. We fix the threshold by setting the
daughter sum rule equal to the meson mass in this limit. The second method
introduces a Borel mass dependent threshold s0(M2). We choose functions s0(M2)
such that the corresponding sum rule is not dependent on the Borel mass
anymore. The relevant hadronic parameter is extracted at the most stable
function s0(M2). The two methods differ in the notion of quark-hadron duality.
Whereas the first method emphasizes errors coming from the simple duality
ansatz, the second method is constructed such as to extract hadronic properties
from the region where the duality approximation is fulfilled best. We use these
modifications of the sum rule approach to extract values for the B-meson decay
constant, the semi-leptonic form factor f+ at zero momentum transfer and the
strong coupling g(BB*Pi). The results coincide with other sum rule analyses.
