+1. Matching the luff as almost well as possible to the fully tensioned downhaul and fully sheeted main allows you to trim for the maximum range of draft depth for the chord. (Having owned a defective mast, I learned this in some detail from some European guys). The wild card in this equation is that the mast bends due to wind force, too, (esp at the top of the rig) and that can absorb some of the luff.