Note that we use 8:1 on the out-haul not so much for its pulling power but rather to get a more precise adjustment. Every inch of pull translates in 0.125 inch of leach movement allowing very fine adjustments.
Officially we are not allowed to have our sails over the black bands but nobody is checking. If you have well made sails the black band can be seen as a maximum indicator. Your sail should not be set passed it. But in the end, as Colin said, it is about sail shape not about the position of the sail on the mast or boom. It is better to look at the sail as a whole rather then at the black bands.
BTW, my sail maker (P&B) used bungee cord as bolt rope. It does not suffer from shrinkage and if it is put under some tension, it pulls the sail automatically forward when the out-haul is released. For this reason it is not stitched to the sail at the goose neck, only near the leech cringle. A figure eight knot held in place by the sail pin at the goose neck puts the tension on. This and a bit of Teflon spray makes my foot follow my adjustments immediately without having to bash or pull the foot. (Did I just say Teflon spray? Must have been an old candle stump!).