Switching themes from custom.html

Hi,

I could use a little guidance on how to implement setting the system theme to either Light BW or Dark BW through both a custom.html and a settings.js file for my app. Does anyone have a link to the code where the Settings/System/Theme menu is from?

I did find this example by @rigrig that switches to the two themes i want to use. Should I try to incorporate this into my code? - Or is there an existing system function for doing this that could be called from anywhere globally?

If anyone feels like taking a look at what i have so far, it's right here. Right now the settings menu only works to set the color on the watch face. Edit: Settings.js is now fixed