Welded/bonded. Once you do it this way you won't go back, I believe that's true of a few things in life.
Welding is quick, less smelly and permanent.
Down side is if you make a mistake it's less easy to fix, I welded the last bag joint incorrectly, I now have a line of weld at the rear of the craft where I had to cut and rejoin once the twist was removed, even doing that wasn't too bad to do.