You have to use a special fuel line in the tank that is designed to be submersed in gasoline.
For some reason it tends be softer. When you over tighten the clamps, the clamps can cut into the hose and cause it to split much easier than normal high pressure EFI fuel line. Even I have done this.
We have changed the style of clamps used and are looking to change them once again to prevent this from happening. We have a few kits out there with the new clamps and none have reported a problem so we are going to start shipping the kits with the new type clamp that cannot be over tightened I hope...
G