Here's a good blog on the topic. What to get straight? Well if your an installer you probably already know all of the ins and outs of solar, and how to get it cheap, the thing about CA compared to West Virginia, is well new homes in CA will definitely want solar, so then the homeowners might be segmented differently, for instance a lot of people that just want to buy and sell, then may want a limited amount of panels to accommodate CA state law, wheres as the segment in Virginia, that 'do want solar', without seeing any state policies probably want a system that will last, and pay ROI, which means a full system size based on the square feet of their home and there average utility output as is... Seeing as though the segment is mixed with demographics of people looking at policies...

https://diy-home-solar.blogspot.com/2019/03/how-many-solar-panels-should-home-have.html