On our Hobie 18 I always used Jake's Plan B, but I didn't attach the bungie to the beam at each side -- I attached it to the dolphin striker on each side with a clove hitch, about a third or quarter of the way in from the hull. That seemed to be the best positioning for the bungies to keep the jib sheets from catching on the mast rotation bar. When the bungies were all the way to the hulls, that left the triangle too wide open, and the jib sheets could still sneak in there.

The reason for using a bungie instead of a cord is because the bungie gives -- if your jib clew blocks or pigtail or bowlines or whatever you use at the clew gets hung up on a cord instead of a bungie, it may stay hung up.

And even in the unlikely case where it might stay hung up on the bungie, it is very lightweight bungie cord, so it will stretch enough so you can still sheet in your jib on the new tack, and the process of sheeting will end up making the bungie let go.