You have heard of the term "downhaul" while reading the forums, the H16 gooseneck has a line tied off to the ring on the bottom, slide gooseneck into sailtrack, run line down to cleat, back up through ring, back down to cleat and crank on the downhaul, this will pull the tack of the mainsail tight, cleat line off.
Rule of thumb, light wind - loose downhaul, heavy wind - tight downhaul.