Six inches to one foot back from the luff is the standard. It goes to say that you want to read the turbulence, or lack-there-of, as close to the luff as possible. You could also use the length of the tell-tail it self to set the distance. Also I think you''d be happier using three sets as opposed to two. Place one set half way up the luff and the others about 1/5 the luff length from the tack and head. Once you''re trimmed and all tell-tails "brake" at the same time, then all you''ll need to watch is that bottom set in the
jib to determine your steering.