I have an issue with a fantail. I'm glad you're all junkies and understand that opening line.
Unless I'm missing something, Fantail's sail just can't be set as designed. The problem is in peaking the yard. Even with the sheets slack, the tension created in the throat and upper luff when peaking the yard enough to bring the boom as far as horizontal is extreme. I've installed a throat hauling parrel, and this helps with peaking but at the cost of very high compression loads in batten 5. Hong Kong parrels help with the set, but again the tensions in what is supposed to be a low stress rig seems outrageous and I've removed them. The throat tension has destroyed the sailcloth in this region - it's paper-thin and torn in places.
The centre of gravity of the sail is well aft of the aftermost tip of the yard. I don't know how much this contributes to this effect, but it is exacerbated in Fantail's case by having a steep sheeting angle (the sheet blocks are not far aft of the batten ends).
The 'compromise' set has as much tension in the throat hauling parrel as 'feels right' to my novice hands, and this has the after end of the boom low and the sail looking like what Jan Barker did to my first-ever love letter when I was 12... sigh...
Any advice (about the sail, that is - the love letter is a goner)?