Yeah Man I don't skimp on clamps or zip ties either, thats cheap insurance..
Have you ever tried "Pinch Ear Clamps" ? They will virtually assure you wont get a barb to tube connection leak.
Just search for them here... McMaster-Carr
I use the single pinch, you can kind of bunch the tubing up with them if you don't watch what your doing, I've never had a problem with it though. They have a double pinch also.
I bought the installation pliers that lets you close them in horizontal or a vertical position. Good stuff....You might want to try them out when you get back. I'll try to take a pic for you later so you can see what the clamps and closure tool looks like.
Hope your GPU is fine...