Hello Gregory, The major 7 symbol simply uses the markup command \triangle with fontsize -3. So simply do something like
\set majorSevenSymbol = \markup\fontsize #-3 \override #'(thickness . 0.2) \triangle ##f The ##f here specifies that the triangle should not be filled. Adjust thickness to meet your demands. Cheers, Valentin
signature.asc
Description: This is a digitally signed message part.