There is no perfect way to do this. On our boats if we start having trouble with the line getting close to the spinnaker blocks we throw the excess cunningham over the front crossbar to keep it off the trampoline. This does not happen too often for some reason.

If you use any kind of bungee you will probably not have the cunningham in the crews hand at all times, there is too much fighting them. If your crew does your mainsheet then they probably do not have the cunn anyway. Once we tried a light bungee holding the cunningham in for one regatta. Eileen did not like it so I took it off.

To make a continuous line I splice really small line to the ends of the 1/4" and tie them together. There is a knot there but it is way smaller than the line so it does not catch in the through-holes at the ends of the crossbar.

Dan