Comment #2 on issue 2586 by [email protected]: StaffSymbol thickness override and imperfect ossia
http://code.google.com/p/lilypond/issues/detail?id=2586
OK, so the real problem is that \override StaffSymbol-thickness doesn't work properly. Take a zoom look at this example:
\version "2.15.39"
\new Staff \with { \override StaffSymbol #'thickness = #(magstep -3) }
{ e'8 [e'] }
Clef, TimeSignature and Beam are slightly bigger than they should be.
Karol
