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:Herbert the Sherbert
C:Martin Ellison
M:6/8
L:1/8
Q:1/4=165
K:Em
"Em" E2 E "C" e3 |cBA "Em" B3 |GBA GFE | "D" FAG FED |
"Em" E2 E "C" e3 |cBA "Em" B3 |GBA GFE | "D" AGF "Em" E3 :| |:
"Em" EFG "D" F3 |"C" EFG "Bm" F3 | "Em" Bef gfe | "Bm" ded B3 |
"D" ded A3 |ded "Em" G3 | Bde "G" dBG |"D" AGF "Em" E3 :|