Render tune title, subtitle and composer in Latex/HTML and not in the image. This way the titles remains a constant size even if the image needs to be scaled. And we have that text appearance under our control. I can't find a way of switching off the tune title in abcm2ps, and have worked around by setting the title format to Y0. Y is not a defined ABC header and is not found in any Dottes tune.

\documentclass[a5paper,landscape,11pt,oneside,openany]{book}