Interesting -- it appears that UA has added the differential-based pricing for B to some TATL routes. I wonder if the two groups -- RM and MileagePlus -- actually talk to each other. The $0 co-pay for B fares is based upon the standard B fare, which is approximately $2800 RT. These discount B fares are new and intended to be a way for them to better merchandise E+ -- an E+ seat assignment will be included at no charge. They started to appear a couple of years ago domestically, but this is the first time I've seen them TATL. (That's why the B fare is different on the two flights on November 1 -- it's priced as a differential from the lowest-available economy fare).

There is a non-zero chance that this is the best pricing you'll see. There's also a chance that they will open upgrade, and then discount award seats later if the J cabin doesn't sell up to their expectations. There are no sure things, and your best bet is just to wait. The cheapest way to get a chance at J is to buy the L/T fares and then hope for a buy-up offer at check-in. For that flight length, I'd guess your offer might go as low as $600 one-way. But, again, there are no guarantees; you may never see an offer that low. TATL from SFO is a very difficult upgrade even with status -- without status, your chances of being upgraded off of the waitlist are pretty slim.