You can change to window mode with windowed=1 on the acsetup.cfg file, but the one in "~/Library/Application Support/Space Quest ][ Remake v2.0 [beta]", not the one inside the application itself.
OMG! Thank you for this info!
Awesome, hint! The Windows version comes with a winsetup.exe program. Does anyone know if there is a similar Mac app? If not, I'd consider writing a little app which can be used to help configure the settings for Mac versions of games created with the Adventure Game Studio.