Oh, just found it! Nevermind...
Here it is in case anyone gets confused like me.
abjad.override(cym_cowStaff).StaffSymbol.color = r"""#(x11-color 'grey)"""
abjad.override(cym_cowStaff).StaffSymbol.line_count = 4
abjad.override(cym_cowStaff).StaffSymbol.line_positions = r"""#'(-4 10 13.6 14.2 15)"""
thanks!