Most people around here use sandworms, but I've had pretty good success this year with nightcrawlers as well. I've also taken a few fish, 24lbs being the largest, using the Berkely Gulp 10" eels on the hook (slathered in smelly jelly for extra scent).
Most of my tubes are 24" long and I run them on either braided or leadcore line with a 30" leader, depending on the depth I'm fishing in. Either way, make sure you have a good swivel in-line or the spinning of the tube will twist up your line. Ball bearing swivels are the best for this.