The Google app requires a menu button (like I have on my Galaxy S4) to access options menu and edit Google Now settings. However, on my Nexus 10 I do not have an option button. Most apps have the "3 Dots" button in the top right to replace it, but the Google app does not have this! How am I supposed to access the options menu in the Google app on my Nexus 10?
The overflow menu for Google Now (on all form factors, I believe) is in the bottom right corner of the app instead of the top right, where most other applications put it. You need to make sure you've scrolled all the way to the bottom of your cards, though, because it shares the bar with the "Show more cards..." button, which is hidden if your screen is full.