To summarize the conclusion ① Regarding sleeping posture, Dream Sleeper will not make it to the sleeping limited ② However, when moving from Tokyo to Osaka with a bed, Osaka → Tokyo has a Sunrise from 0:30 departing at 7:08, After leaving Tokyo at 22:00, get off to Himeji to Mincho Himeji and get off at 5:25, and you need to get back to Osaka at the new speed. If you do not need to stay up late, you can not get much sleep. Because the required time is too short for the Sunrise issue, the possibility of losing sleep is high. If it is Dream Sleeper, it will take about an hour to go to bed.
③ The service level (amenity, Wi-Fi etc.) is higher for Dream Sleeper, but the Sunrise Shower is attached.
④ Because Dream Sleeper can ride only 11 people a day, it may be hard to get a ticket from the sleeping limited express.