  The Doppler backscattering (DBS) diagnostic, also referred to as Doppler
reflectometry, measures turbulent density fluctuations of intermediate length
scales. However, when the beam's wavevector is not properly aligned
perpendicular to the magnetic field, the backscattered power is attenuated. In
previous work, we used beam tracing and reciprocity to derive this mismatch
attenuation quantitatively. In this paper, we applied our model, in the small
but finite mismatch limit, to a several new cases. We compared our predictions
with multiple O-mode channels for the first time. We then identified a $\sim
3^{\circ}$ error in the MAST Q-band's quasioptics, showing that our model is
useful for commissioning DBS diagnostics. For both O- and X-mode, we compared
experimental data with our model's predictions at multiple times during the
shots, unlike our previous work, where only a single time was analysed.
Finally, we analysed other contributions to the backscattered signal,
evaluating how much they affect our measurements of mismatch attenuation,
giving comparisons with data from both MAST and MAST-U. This paper's detailed
study systematically validates and demonstrates the usefulness of our model for
quantitatively interpreting DBS data from spherical tokamaks.
