tube and worm

Does anyone out there use the tube and worm technique. I have fished it a bunch of times these past few years and I think I could be doing alot better than I have been. I have caught some fish using this method but I think there is always room for improvment. Most of the fish I have caught were within a few minutes of putting the tube over the side, I have noticed that when I drag them for any period of time I notice that the worm is cut off where I inserted the hook so i am left with only a very small piece remaining. I think it is being cut off when the tube pinches against the hook. does anyone understand this problem? How far do you let the hook extend past the end of the tube? Are you using trolling sinkers ? Thanks for any help you can give.