Then go for it with the dual systems, just ensure there is no way to interconnect accidentally and you will need approval from your power company (at least we do here) if you want a net metering situation and for the grid tie portion. You will need to take care with how you handle the non-grid tie and make sure you program the battery charger correctly for golf cart batteries.
Finally, I would like to offer up my roof for any extra space you may need for south facing (I designed it specifically for panels 15 years ago thinking someday I might be rich or panels would be really cheap but neither have happened). I have even removed the 140 foot tall poplars that provided shading.
