Dude i think you got it all wrong i have off grid 7200watts 6750 watt continuous i mean i can run that 24 hrs a day....
I put in my new home and planing was done way before roof was installed people do not realize the importance of the Pitch of your roof this will determine amount of sunlight hrs you will get
down fall it was over 15,000 and another 3500 to put in .. this is something you actually leave for the pro's and from what i have learned is efficiency is not how you think of it its most efficient panels use less space for instance my set up i have 27 - 250 watts solar panels black base daily watts based on 5 sun hrs is 33,750 watts its all about getting the best power performance and that is actually having it in the correct orientation and direction also important is air flow solar panels do not like Hot and will perform better at the proper operating range i have already talked to them about another set up that actually follows the sun but ground based units