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.

X: 1
T: Constant Billy
A: Headington
M: 6/8
L: 1/8
P: A(AB)4
K: G
P: A
D |: "G" GBd B2 B | "D7" cBc A2 A | "G" BAG "C" EFG | "D7" DEF "G" G2 D :|
P: B
|: "G" Bcd "C" ecB | "D7" ABc "G" dBG | "G" Bcd "C" ecB | "Am" ABc "D7" def |
"G" g2 d B2 B | "D7" cBc A2 A | "G" BAG "C" EFG | "D7" DEF "G" G3 :|