usually nothing gained... having only frontwheel brakes, it'll plough on ahead
what car?
TA05 has both centre & diff oneways; to use diff oneway at rear
you'll need one that's oneway in the opposite rotation to the front.
AFAIK nobody makes such a beast.
With a bit of DIY ingenuity you could mount centre oneway pulley
to run the rear belt...
Some shaft cars like TB02/3 & TBevoIII/IV/5 can be set to run either way
so you can make a 'front' oneway to work fine at the back (motor reversed).