I'm fairly new to it as well (last May), and I'm still tuning my sails (2011 Overdrives 11lw & 9.7), but I've found one consistent thing across both of them and the CR 11 I had for the first few months: the downhaul range is small 10-15mm at most (outside that the 9.7 in particular is awful), and the outhaul tends to be huge.
I have my boom set @ +4cm by default, and +6cm if I think it may get a bit too windy for me. All of the of the sails still work, even @ +6cm, though they lose all bottom end and I can't rail the board well or at all, and angle up and to a less extent down is greatly reduced. Higher winds are more manageable though, at least for my current technique, so I can keep sailing without changing anything else.
When it's really light I frequently have the outhaul set slightly negative when pumping and pulling a little on once planing.
I can't adjust my slalom outhaul nearly this much before it's unstable (3cm max range on my North Rams).
The main thing I've learned is that the range is huge and I'm the limiting factor, which leaves a lot of room to improve performance. Every sail is kind of a series of several experiments, some work, most don't, really good fun.
Up-wind you pull on the out haul to balance the sails power in your hands.
Down-wind you release the out haul to make the sail as powerful as practical.
Generally speaking I release about 10cm when I go around the top mark. Note: I always release out haul, even in super over powered conditions as it makes going down-wind more comfortable regardless.
Upwind sail nearly kissing the boom up to the harness lines (though I am using a large slalom boom not a extra wide formula boom), more out haul if it howling.
Downwind let off the outhaul so the sail is is spilling over the boom (even if it is high wind just use the chicken strap and go deeper).
I have the 11m overdrive, I found AUS691 measurements spot on, I rig the same way :-) and I am still a beginner at this.
Thanks all, I have clearly been miserly with my outhaul on the downwind legs and probably not quite enough upwind. Too used to 4-5cm range on slalom sails! Appreciate the help.