I'd run those bungies parallel to the hull from front beam to rear beam (using micro blocks riveted to the beams), with a block on the rear through-hull to direct the final portion of the bungee across the tramp to the opposite (front) through-hull and to the trapeze.

For the skipper, a similar system is used, except the final section would be routed from the front beam straight back to a grommet on the rear of the tramp, and up to the trap line.

If you were into redundancy, you could make each trap bungie separate, so if one breaks the other three remain..

If you need a lot of stretch, you could double the bungie length by adding more fore-aft lengths (and double the block)

This keeps the bungie lines from catching stuff under the tramp if the lines go slack. Also easier to re-route if it breaks.

Did I confuse you?