I did just as DMRBG did but used 1/4" nylon rope. Place a screw in eye bolt near each end of the barrel (4 total) and tie one end of the rope to an eye bolt. Next thread the rope through the additional bolts in a criss-cross pattern and tie a loop into the rope about 12 inches from the last eye bolt. Now thread the rope through the loop and back to the last eye bolt and tie it off. The loop will just add leverage when you pull to tighten the rope. I did this by myself and it worked well but would have been easier to get more tension with an extra set of hands. I'm not the best at explaining things so not sure if this helped or not. A picture speaks a thousand words.
