I understand the basic principles of sailing but in order to improve my racing performance I am trying to find more information on tuning. I am trying to understand how mast rotation, downhaul, belly etc etc all interact under different conditions to effect performance. My ability to point upwind for example is poor and I am unable to achieve 50 degrees which I believe I should. Can anyone tell me where I can get advice on setting up the boat to achieve the best from it under different conditions.