Here is a good video on finger positioning. There are many ideas about this, but basically, you want your fingers slightly apart, not together, and not wide apart. The goal here is to produce turbulent flow between your fingers, thus increasing the effective size of your hand.
You can experiment with various hand positions to see what is the most effective position for you. It may not be what you might intuitively think it should be.
Another advantage to this hand position is that it can be more relaxed than other positions, and that is always good for your DNFs.