I kind of tried a couple of glass rattles in the craws, which seemed to work well. If you take a old telescoping car antenna, you can find the right diameter to core out an internal cylinder that makes a perfect spot for the rattle. They also make a coring tube that's for sale in certain fishing catalogs.
But I totally agree Al, the number of cues in your favor could mean a few more strikes during the day, and possibly help you win a tournament.