Directly measure electrical performance of the clock source with scope.
Connect clock source to the calibration trace on one of the Mux EVM and measure electrical performance of the clock signal passing though the trace with scope.
Connect clock source to the input of the Mux EVM and measure electrical performance of the output of the Mux with scope.
Repeat 1-3 and measure the electrical performance of the output of the other Muxes with scope.