Be aware that the seats are not determined by Boeing, who builds the planes. Each airline chooses their own interiors, so the seats in a UA 787, and ANA 787 and a Thai 787 are all quite different. I've been on the ANA and the Thai 787 and I reported that we found the seats on the 787 uncomfortable, while the Thai seats were very comfy. Be aware that what is uncomfortable to me may not be to you.

Thanks for your input, Kathie. The main thing is that I'm happy we are able to fly business class with FF miles. Although I'd like to maximize the chances of a really comfy seat, that's secondary to being able to do the flight. I can probably figure out a way to modify the seat with a pillow or blanket. I'm short and sometimes my feet don't reach the floor, so anytime there's a footrest, I'm a happy camper.

Uh-oh, I just read about UA's new business class product, Polaris. Need to do some research as to when and on which routes it will be available. Back to the drawing board.

Most folks on this site are do-it-yourselfers. My small experience with airline points (not UA) convinced me it is more effective to phone the airline issuing the points and talk the complications through with an agent.

My strategy is evolving: In checking UA's online site for "if we flew today" options, I'm finding better availability than booking on the first day of availability for our October 2017 flight. So, I'm going to book whatever happens to be the best option on the first day of availability and change the reservation (paying the fee) if something better shows up before we travel. Now on to other aspects of planning the trip.

A sincere thank you to everyone who contributed to this thread. You were so helpful (as usual)!

Checking in to report that I booked our one-way flight from Japan using UA award miles in October 2017. We're flying nonstop from TYO to SFO on ANA's flight 8, a 777-300ER. I followed the helpful instructions provided above and phoned ANA immediately to book seats. I got the seats we wanted by checking seatguru.com before I phoned. The ANA rep was helpful, patient, and customer-oriented.

Thanks a bunch for stepping me through the process in previous posts to this thread.