In my experience and from every article I've read/video I've watched, the answer to that question is going to be dictated mainly by the depth of the water in the reeds. In this particular tournament, there was about 2-3 feet of water on the edges and then 2 feet or less of depth once you got about 10 feet back in the reeds. In practice, I did mess around with pitch far back into the reeds and managed to get a few bites from small fish. Looking back, I'm sure that there were quality fish somewhere on that lake further back in the reeds.
Last year, Aaron Martens won a Bassmaster Elite Series event on Lake Havasu by doing something very similar to this. If you can, watch that video of the tournament. There's a lot of really good info that you can pick up simply by watching how he tries to present his bait to the fish that are way back in the reeds.