do you have to deal with 'float' in Ctrlr? if you want it to reset centre, that's 0.5 on a 0 to 1 range, even if your values go eg: -1 to +1(it would reset at value=0) but that's SE speak -please gen me up on Ctrlr.
there's great module for SE, DD doubleclick reset, which offers random as well, i use that for all my control objects.