  The flow properties of confined vortex matter driven through disordered
mesoscopic channels are investigated by mode locking (ML) experiments. The
observed ML effects allow to trace the evolution of both the structure and the
number of confined rows and their match to the channel width as function of
magnetic field. From a detailed analysis of the ML behavior for the case of
3-rows we obtain ({\it i}) the pinning frequency $f_p$, ({\it ii}) the onset
frequency $f_c$ for ML ($\propto$ ordering velocity) and ({\it iii}) the
fraction $L_{ML}/L$ of coherently moving 3-row regions in the channel. The
field dependence of these quantities shows that, at matching, where $L_{ML}$ is
maximum, the pinning strength is small and the ordering velocity is low, while
at mismatch, where $L_{ML}$ is small, both the pinning force and the ordering
velocity are enhanced. Further, we find that $f_c \propto f_p^2$, consistent
with the dynamic ordering theory of Koshelev and Vinokur. The microscopic
nature of the flow and the ordering phenomena will also be discussed.
