I did a little bit more digging myself and found this file, which contains the command used to launch ScummVM:
/usr/lib/python2.7/site-packages/configgen/generators/scummvm/scummvmGenerator.py
I managed to do what I want by adding "-b", "1120" to the commandArray defined on line 38.
What would be required to add this into the UI? It would make most sense to configure it per-game, if possible.