Hi greenrvgreen,
Here is what to do!
Start with an energy audit *grin*.
Build up the battery bank based on 4 to 10 times daily consumption. I'd lean towards 6 times if that is feasible. Wire the battery bank in a balanced manner.
Design the solar wattage based on what services the daily wattage allowing for solar isolation hours for your location *or* the minimum of 60 watts per 100 amp-hours of storage. Choose the larger number.
Choose the highest voltage panels that meet the number of watts from the above, and that fit the "real estate" on the roof.
Find a charge controller that will handle that voltage and 125% of the wattage. Pick one that can do diversion loads if possible.
Plan the installation with zero shade.
Run 4/10 uv resistant wire from the panels to the combiner box, and 4/10 from the combiner to the charge controller. Run 4/10 wire from the controller to the battery bank.
If diversion loads are possible install a 12 volt element in the water heater. Use 2/10 wire.
Sit back and enjoy not paying for gasoline.