Tom,

Yeah I got a few idea's for you.

You can fit a bungee to the mast rotator arm and have both its ends tied off to the spi pole some distance in front of the mast.

Another option is to tie one end of the bungee of to the boom and then go in front on the mast one time and tie the other end off to the same place on the boom.

In either case you need to kick the boom over in light airs but then it stays there.

I never rig these as I always use my jib cleats and two small line to pull the mast rotation arm over in light airs. When sailing two up it is a task I delegate to my crew (often myself incidently) as they will be on the leeward hull anyway.

The underlying principle if the same for either setup. See picture.

Basically the overall line length for the loop is longer when the mast and boom are aligned with eachother. This stretches the bungee cord. When the mast and boom are perpendicular to each other then the total length of the bungee is the shortest. When using a thick bungee cord the axial force in the loop is sufficient to pull the mast to side it is set. Working against the rotation limiter, so you can still adjust your mast rotation the normal way.

Numerous variation of this principle are possible. Using cleats etc. Where two pieces of line are fic to the mast and the run in front of the mast back to the boom and two individual cleats.

I'm not going to describe them all, so what are you looking for exactly. Something that is really simple and works or something that work really well but has you riveting eyestraps to your mast etc ?

Wouter