If you are launching your script from a desktop shortcut, then in /usr/share/applications/hildon/xyz.desktop, type this line: "X-App-Loading-Image=none". Then it will not attempt to launch a window when you click the shortcut.
I know recaller, I use recaller, but I would gladly find something more directly connecting to the audio, if possible. Shortcut instead of widget, bash script instead of python...
Thank you. Best wishes.
_________________
Per aspera ad astra...