Thanks for making the answer so clear, John, as with all your advice. A while back I asked how to get rid of lee-helm, the answer came from John : Rake the mast back until the lee-helm is neutral, or at least not too unmanageable. Then rake rudders forward so that the weatherhelm upwind from increased mast rake is not a problem. It`s still there, it still loads up the rudders, but it isn`t transferred to the tiller, so you get to keep your shoulder joint in one piece. Apparently some weatherhelm helps the boat track upwind as the loaded up rudders create lift. (If I`m mis-informed here please don`t kill me, I spend my time designing buildings, not boats, and very seldom consider the hydrodynamic properties of concrete, although I imagine they`re not worth discussing. No, this is not an invitation to ressurect the thread about concrete canoes ).
Although my boat was designed without a spinnaker in mind, I`ve found that this advice has helped tame the rudders.

Cheers
Steve