RE: I hate my climber....
You might be able to do away with the bungee cord. use a small rope about 3'-4' long, tie it to the bottom piece of your climber, this will stay tied to the bottom piece at all times. After securing both pieces of the climber on a tree tie the top piece to the small rope already attached on the bottom piece. Now if your foot(s) slips out of the bottom piece while climbing it can't fall down out of reach leaving you stranded.(that's the main purpose of the bungee cord)