backwards the pull refers to how much cable they pull
short for calipers, cantis and a small number of specially designed linear pulls and discs
long for the vast majority of linear pulls and discs.
Some adjustable pulls(designed mainly for long pull applications) can be adjusted down close to short pull.
you can if you have to use a long pull lever with a short pull brake but leverage will suffer.
Problem solvers makes a pulley for using long pull brakes with short pull levers... maybe you could rig it backwards.