To close the loop: I took the dayroom for 5 hours (worked out to $45). It was around a 6 mins walk from the ANA Business lounge. The room was't anything fancy, but clean and functional.

Both the flights on the 787 - BOM-NRT and NRT-SJC - were very comfortable. Flying the 787 (or the A350) does make a big difference especially if you have back-to-back long haul flights. The pressure and humidity is far easier on the system.