I have been triing to find some advice or information regarding sail shape. I have 2 sails, the first one is fairly old and has a flat shape, ie when on the beach and sheeted in the top section of the sail(up to batton number 3)is very flat, then from there on to the bottom of the sail a decent pocket is formed. I had a new sail made by north sails about a year ago. This sail is not flat at the top, and has a very curved shape causing a very closed shape to the sail, and boy o boy i cannot get it to perform. I have tried everything to get the top of the sail flatter as i find up wind the boat wants to stall very easily compared to the older sail.i Have tried less to no batton tension i have tried lots of downhaul! What sail shape should a hobie16 have to perform well?