I am shocked that anyone would do PV and be considering electric DHW. You do realize that solar hot water is about 5x the efficiency of PV (it might be closer to 10x)?

I am curious what your estimated heating needs are? Propane matched with PV seems strange to me. Ah - but you are in CA. I guess that might make sense with your electric rates. But please heat your water with solar. I would consider solar for running the radiant.

200k btu seems like a lot. I'm assuming you are at elevation. But even still that seems like a lot. I am in a similar size house and I am under 100k btus and only because a/c drives the sizing here. We get under 10 degrees (but not often).I think man J puts our heating needs closer to 50k btus.

I am similarly surprised that PV makes sense in a second home situation unless you rent. But typical second homes used 10-20% of the time are hard to justify PV even at $.40 a kwh. I'm curious what you get to sell at, because around here we just get $.15/kwh. So even with Fed and state rebates and a subsidized selling market, it takes a good sized southern roof to justify PV (in a $ sense).