I was thinking how that Shush!-like functionality could be implemented. This seems a reasonable way:
Opening the app gives you the three options as in the current version (normal, vibration only, silent)
When pressing either vibration or silent you get a second screen with 3 predefined time intervals, which are configurable in the Android app (e.g. 1 hour, 2 hours, 8 hours).
If you DON'T press any button in the second screen within let's say a minute, then the selected mode (vibrate, silent) will be set indefinitely until you change mode again manually.
If you DO press any of the 3 options, the selected mode (vibrate, silent) will be on for that specific period of time and after that period of time the phone will automatically return to normal mode.
At any stage in the app, I would like to see it returns to the watchface screen after a certain timeout.
Don't feel obliged to implement this, but I would really love this and even willing to pay for it. Too bad I'm not a programmer otherwise I would build it myself :)