Hi,
I agree with TallJames... the tip of the 2nd batten (the one above the boom) should not be away from the mast otherwise the sail is too tight and it will not 'breathe' (ie 'inflate' as the wind pushes it) while sailing.
That said, I believe the right amount of downhaul is key for most (if not all) sails/masts and that should set everything correctly. If this foundation is not correct, you'll go nowhere. The most common mistake I see on the beaches is 2 to 4 inches between the pulleys at the bottom of the saild and the extension: this is way too much! Aim for 1 inch.
Eventually, there is always a percentage of personnal feelings but this should be quite minor nowadays.
Hope it helps.
Cheers