I've used the San Francisco yeast to make a Marzen, which I fermented at 50 degrees, and I was pretty disappointed. The beer was very clean and smooth, but I think this yeast is a hop accentuator, and mutes malt flavors. Which the BMC drinking group loved, BTW.
Maybe it would be better fermenting at a higher temp, but I've made California Commons with this yeast too, and they also come out more hoppy than malty, which I personally don't prefer in my German beers.
I suppose you could play around with greater amounts of Munich malt, or add some crystal, etc. but using the right yeast in the beginning is so much easier.
The White Labs WLP800 series will give you FAR better German lagers, IMHO.