  Hot subdwarf-B (sdB) stars in long-period binaries are found to be on
eccentric orbits, even though current binary-evolution theory predicts these
objects to be circularised before the onset of Roche-lobe overflow (RLOF). To
increase our understanding of binary interaction processes during the RLOF
phase, we started a long term observing campaign to study wide sdB binaries. In
this article we present a composite-binary-sdB sample, and the results of the
spectral analysis of 9 such systems. The grid search in stellar parameters
(GSSP) code is used to derive atmospheric parameters for the cool companions.
To cross-check our results and also characterize the hot subdwarfs we used the
independent XTgrid code, which employs Tlusty non-local thermodynamic
equilibrium models to derive atmospheric parameters for the sdB component and
Phoenix synthetic spectra for the cool companions. The independent GSSP and
XTgrid codes are found to show good agreement for three test systems that have
atmospheric parameters available in the literature. Based on the rotational
velocity of the companions, an estimate for the mass accreted during the RLOF
phase and the miminum duration of that phase is made. It is found that the mass
transfer to the companion is minimal during the subdwarf formation.
