Hi,
I would use a two-note tremolo, with the option "Outer tremolo touching stems", by selecting it in "Appearance > House Style > Engraving Rules", as the manual indicate.
But this operation don't work for me, even after restoring appearance, tremolo remains in the default appearance "between the stems".
I have a mac (osx mavericks) and my version of Sibelius is 7.5.
Anyone have a solution?
Thanks!