That dual cable dual activation trick has been used for years in the British
Isles for those afflicted with automobile trials.  No 4WD here.  Plain rear
wheel drive with a set lever and two compensator levers.  The set gets the
brake shoes close to the drums, just like your normal "parking" brake.  The
other two levers act independently on the cables to allow judicious
application of braking force to the spinning wheel.  Requires a certain
amount of "touch".

You would be amazed what an old Cortina can do with this set up.

cheers,

pensioner