Lots of different opinions on this, even among the experts. Most seem to agree that the main grip should be with the weak hand, but just how strong that grip should be is the question.
Too much grip with the strong hand screws up fine trigger control for many people, but not all. Here's a pic I took of Doug Koenig at the Nationals a few years ago. Doug's one of the top shooters out there and he's obviously using a pretty heavy grip.
