Design MGM and MGU;
Note: During the design process, these numbers are determined based
on a normal mast. Most masts have slight curves, these curves are
not normally a factor but they can cause very slight variances in
the stated numbers.
Some mast have extreme bends, when these curves are cut into the
sails luff, they can make greater variances, as much as 6" in the
stated upper MGU, ask if you have a question.
Normally, roach is the first thing designed into the sail. See other
help topics on sail roach.