Trapeze wire 'keeper'

Can't think of a better term for it, but I'm referring to the short piece of shock cord connecting the two trapeze wires at spreader height. I had this on the Contender, but don't remember whether the length wants to be:

1. Such that when both wires are bungeed at the gunwhale, neither can slip round the wrong side of the shroud i.e. shockcord just under 2 speader lengths; or

2. Such that when both wires are un-bungeed,  neither can slip round the wrong side of the shroud i.e. shockcord just under 1 speader length.

I guess, on the water, its only case 1 that is important?

This elastic stops the trapeze wire getting caught around the spreader, principally after a capsize.  Mine is pretty long (doubled) so it forms a large loop and is probably about 800mm of 4mm bungee - its just tightens sufficiently to stop the wire flopping around the front. However, I notice the other contender at the club has a much neater arrangement using a single, much shorter length of thinner bungee (probably about 500mm) tied to the trapeze wires and passing in front of the mast just above the spreaders.