Jim is dead-on. I seem to have a higher catch rate away from the boils, but still push up to them to see what is going on. The flats are great, too. I catch a bigger variety of species in or near the flats than in the actual channel. My assumption is that the channel acts as a highway of sorts and the flats are feeding/holding areas, so your luck would improve since there are more fish in the area. But don't take my word for it, spend a few days out there and test out my theory. By the way, weekdays are much better due to the lower number if boats (and less idiots who zoom in and out of the channel...that's my pet peeve there) affecting the fish, especially the larger ones. And yes, Travis, big stripers DO exist and they can be caught at the GSP.
Chris