I have a 5.0 and 5.8 and as the guys say put the boom on before any downhaul,
I run zero outhaul and sometimes even a little negative,
you can over downhaul the 5.8 but the 5.0 seems to like a bit more on it.
I ran a X3 mast for a bit at the start on the 5.8 and it is way too loose in the leach causing it crease the monofilm from flapping like crazy when going upwind, I now run the proper KA 70% mast and it is sweet.
In the 5.0 I run a 400 fibrespar tidal wave that I always used in my ezzy wave sails and it sets and runs sweet,

these sails have got me over 40 knots with no problem and are very stable and comfy of the wind.