[GuyBFF]

That's all I've been using, but I made sure to get the clamps with the flatter area under the screw (or else they leak right there on tubing which won't impression). Some have more of a bulge where the screw is crimped on. You could also try the crimp rings, all the guys setting up drink machines swear this is the only way to go, but you need the right tool. Lastly theres high end screw clamps with totally smooth insides, but I don't think you should need to go this far.