what is optimal genoa size for H30 (74-83 series). I purchased a 77 H30 and it is covered so I can not get the exact measurements myself without taking it apart. The specifications list the size as I 40'6" and J 12" What do owners that own one suggest for these lengths? I think I have standard rig. I have the deep keel version (5'4") draft. Thanks and happy sailing...