[Al Skierkiewicz]

One little item no one has mentioned here is the switching frequency of the individual controllers. The Victor is 150 Hz while the Jaguar is 15 kHz. At 50% throttle the Jaguar would switch an additional 50 times during the period that the Victor is turned off. Although the motors are linked and there would certainly be some flywheel action provided by the transmission and coupled mechanism, I would suspect this would be bad for the Jaguar. The net result on the mechanical output is dependent on the stored mechanical energy in the rest of the system. As to differences in linearity, the two motors are coupled and the result would be a combined speed slower than expected. As the two motors both will supply power, it is a matter of which is providing more power. In this case I believe the Victor supplied motor will be contributing the majority of the power below about 75% throttle. At full throttle there is little difference.
In the case of the series wired motors, the current is theoretically the same in each motor. However, the production variations in inexpensive motors will affect the output power vs input current. The result is that the power output of the transmission is never fully shared by each of the motors. One is always providing more power than the other.