When you nurse, do you use one or both breasts at a session? I usually use only one. If I need to pump (which I don't very often, as I stay at home with my baby and nurse her all day), I will nurse her on one breast first thing in the morning, and immediately pump the other breast--that's when my breasts are at their fullest. This way I don't disrupt her feeding rhythm (i.e. we don't miss a feeding).
Also, I notice that when I first pump after several weeks without pumping, the output is small. But just the pumping action (even if I get less than an ounce) is enough to stimulate my production so that within a day there is much more. So, yes, in my experience dry-pumping does help.