Ideally, it's always best to follow the method of + and -, rather than only +. In stack mode, I'm often detuning a width of twelve digits. This is obviously necessary for string patches. So, I follow the method of keeping everything as close as possible to "0," so that I'm tuning in the +6 and -6 range, rather than the +12 range. This makes sense even if you don't play in an ensemble but alone, since it will help to keep the one synthesizer in tune with your other instruments.