I am not convinced that a 270 auto would work. Firstly the RRPM have to be recovered, then the height loss in the turn and any inbalance would add to the rate of descent.
I would stay on the x wind heading and accept the fact that I would have to flare across wind, but would be closer to the shore.
It does depend on the wind speed though. If the wind is strong then a slight turn towards the wind would give a better landing and the distance out would not have increased very much. In light winds it would be best to make it towards the shore.
Here is a thought...If you were autorotating downwind, you flare, and just as you were levelling for touchdown applied full pedal so that the landing on the water was in a backwards movement. Would this not, give you the best chance of survival?