Wow, that's even a more interesting feature to figure out and discuss
...but I guess it should mean to add complxity to a concept that has its strenght on simplicity. At this point would be better to get the retro-direct mech compact and boxed close to the motor and run a single speed chain. An heavy duty BMX chain, althoug stretchable, is able to withstand many KW.....any deviation from a perfect chainline lowers drastically its performnce, though.
A double output (one for each shaft end) with different gearing and a double (or a redundant quadruple
) freewheeling system, with this single stage setup, could make sense. For a non-single stage, otherwise, a boxed retro-direct assembly and a single trasnission chain/belt is the more sensible approach, I guess.
Waiting keen for next pics, details, and runs