As I've posted a number of questions about travelling from NRT to Kyoto, I thought I'd report on how it went.

Landed in NRT at about 12:40. Cleared passport control, etc. in about 20 minutes. Went downstairs and easily found JR ticket office. Asked for NEX tickets and Nozomi Tokyo-Kyoto-Tokyo tickets. TA suggested buying Kyoto-Tokyo at Kyoto. She printed out three tickets, on one she wrote Kyoto Zone, the other two she circled car/seat numbers (we didn't ask for reservations). Paid by credit card.

A bit of confusion as to which ticket to put in the automatic gate (seat reservation ticket alone is not sufficient, and the guard kept asking for our non-existent JR Pass), but that resolved quickly.

Car numbers painted on the platform. Caught the 13:16 NEX, arrving Tokyo 14:10, precisely on time. No problem following the signs to the Shinkansen. Caught the 14:33 Nozomi to Kyoto with about 10 minutes to spare. Ordinary car was fine. It was almost full. Conductor bowed every time he entered the car. Arrived Kyoto 16:53, again precisely on time. Found the 17:00 hotel bus for the Westin Miyako with a minute or two to spare. We were in our room by about 17:30.

Thanks to all who indulged my obsessive questioning on logistics.