Admittedly, there's a 100 different ways to accomplish something. I prefer things simple so what I did was to cut out a section on the bottom of the fuse between formers large enough to put a foam wrapped battery where I wanted it. Once opened up, I used pipe insulating foam to wedge everything in tight. Then I used 3 cut to size pop-cycle sticks as cross members between the packed in battery and the balsa edges remaining on the fuse bottom. These were pushed in between the foam and the bottom. This effectively creates a floor for the battery's weight which is structurally sound and won't shift or move with vibration or during flight. Next, I simply ironed white Ultrakote over the opening which can be removed and replaced if you ever need to get to the battery compartment. There is no weight or stress placed on the Ultrakote covering.