Changing the size of layout objects

The font-size property can be set directly, so that only certain layout objects are affected.

\version "2.24.0"

%% http://lsr.di.unimi.it/LSR/Item?id=412


\relative c'' {
  \set fontSize = #3
  c4.-> d8---3
  \override NoteHead.font-size = #-4
  c4.-> d8---3
  \override Script.font-size = #3
  c4.-> d8---3
}