As indicated in the previous post, shroud tension influences rake, mast prebend and headstay sag. Likewise for fixed backstay tension, but in light to moderate conditions it's best to adjust the turnbuckles so the block rises to the top of the split backstay allowing you to depower using the adjustable backstay.
Maximum rake with the mast step forward gives you just a touch of weather helm in light to moderate conditions, providing some lift from the rudder. It does depend on having enough weight on the rail to maintain a reasonable angle of heel. If your crew is underweight and the boat is heeling over too much you don't need more weather helm.
You don't want so much weather helm that you are dragging your rudder through the water upwind. It may be the modified rudder, but I also wouldn't want to have 'no hands' like the picture in the rules thread.
Regardless of where the mast step is set, I think an excessively saggy headstay also hurts pointing. Since shroud tension is so much higher than headstay tension I'd theorize that adding a few turns isn't going to reduce mast rake. As wind speed increases and you begin to heel more, you can depower by adding turns to the shrouds. Since you don't need more weather helm why not maintain the same mast rake by adding turns to the headstay?
