One person, same SF, oil heat / hot water and my new bill is $90ish (240ish kwh). Up from $65ish last month with similar usage. Sucks, but my bill hasn't tripled.

Having an extra person shouldn't, in itself, triple your usage compared to mine. Do you have large draws like: gaming computers, a hot tub, electric heaters, etc? If not, I'd spend some time to figure out where your draws are before spending thousands of dollars on solar.