BTW I am considering something like this. What slows me is that I'd need to cover two separate roofs one south facing the other west. The second one being quite elevated.
Also when it comes to backup power, a 10 KW Genset will come cheaper than any battery. Therefore IMHO 10KW On grid + Genset, if really needed, is the way to go these days. But in 3 years time it could all change.
And than I am not in a remote area, where for new houses, the cost of a PEA connection comes into the equation