I use a text editor that allow a line up to 1000 characters long. Yarn
folds this line into several lines when the e-mail is packed into the
SOUP file. So I notice how the CC: is folded from the e-mail I received
and do the same (insert a carriage return after a coma) . I think
multiple CC: lines also work but I have not tried it. You can always test
to see how and if something would work. Each system has some little
quirks that you can find out by sending test messages.
Hope that help.
Good Luck.
Tuan