Hey Tom,
Be careful with using electricity for hot water. Just be certain that your hot water tank is filled with water. If the electrode is not covered with water when you hit both switches to ON, you will fry the electrode. I did it in my last TT. Gave me all sorts of electrical fits until I figured out what had happened.
Don';t get me wrong, it can be done and you can use both electricity and gas at the same time on the DSI models. Gives you fast recovery times. Just make sure you have water coming out of your hot water taps before hitting the inside switch.
Best of luck and let us know how you come out.
Jim