SFO is usually served by A333 - this cabin has an alternating 2-2-1/1-2-1 abreast layout.
You may find more info in the
http://www.flyertalk.com/forum/finna...er-thread.html.
The seat width is reasonable and the good thing is that seats have much the same width all the way down. Width at feet level varies by seat in the cabin, but all are better than the A350.
Seat selection is free of charge in business class, and can be done at time of purchase or later through manage my booking.
I suggest you go for one of the L seats, with 1L with least limited width at feet level and very easy aisle access and 2L/4L/6L with slightly more privacy. 2A/4A/6A is also a great choice, but has those foot cubbies that limits you.